SCERT Maharashtra Question Bank Solution Science 1
SCERT Maharashtra Question Bank Solution Science 1 all Questions and Answers for 10th Std. Subject Science and Technology 1. Here we have given accurate answers by Maharashtra’s Top Teachers. All Questions Answers will helpful for Maharashtra SSC Exam 2023. इयत्ता १० वी प्रश्नपेढी २०२२ – २०२३.
Que. 1 B)
I.) Find the correlation
1.) Eka boron : Scandium :: Eka Aluminum : ……..
Answer: Eka boron : Scandium :: Eka Aluminum : Eka Silicon
2.) Mendeleev’s periodic table : atomic mass :: Modern periodic table : Atomic number.
Answer: Mendeleev’s periodic table : atomic mass :: Modern periodic table : Atomic number.
3.) Group 1 and 2 : S block :: …… : P block.
Answer: Group 1 and 2 : S block :: group 13 and 18 : P block.
4.) Group 13 and 18 : P block :: …… D block
Answer: Group 13 and 18 : P block :: Group 3 to 12 : D block :: ……
5.) Two elements in the same position : demerit of Newland’s octaves :: place for Isotopes :…….
Answer: Two elements in the same position : demerit of Newland’s octaves :: place for Isotopes : Demerits of Mendeleev’s periodic table.
6.) Beryllium : alkaline earth metal :: sodium: ……
Answer: Beryllium : alkaline earth metal :: sodium: Alkali metal
7.) Cl : halogen group :: Ar : …..
Answer: Cl : halogen group :: Ar : noble gases
8.) Iodine : solid :: bromine : ……
Answer: Iodine : solid :: bromine : liquid
9.) Electric motor : converts electrical energy into mechanical energy :: electric generator: ………………
Answer: Electric motor : converts electrical energy into mechanical energy :: electric generator: transforms mechanical energy into electrical energy.
10.) Fleming’s left hand rule : electric current :: Fleming’s right hand rule …………
Answer: Fleming’s left hand rule : electric current :: Fleming’s right hand rule : Indicated direction of induced current.
11.) Alternating current : oscillatory :: Direct current:……….
Answer: Alternating current : oscillatory :: Direct current: Non-Oscillatory
12.) When ice is converted into water : constant temperature :: before the water evaporates : ………………….
Answer: When ice is converted into water : constant temperature :: before the water evaporates : temperature increases.
13.) Relative humidity greater than 60% : saturated air :: relative humidity less than 60% :: ………………….
Answer: Relative humidity greater than 60% : saturated air :: relative humidity less than 60% :: Dry Air
14.) While studying anomalous behavior of water in Hope’s apparatus, the upper temperature of the thermometer : 0°C :: lower temperature of the thermometer : ::………………
Answer: While studying anomalous behavior of water in Hope’s apparatus, the upper temperature of the thermometer : 0°C :: lower temperature of the thermometer : : 4°C
15.) The density of water is high at 4°C : anomalous behavior of water :: shredded ice converted into solid ice balls : ………………
Answer: The density of water is high at 4°C : anomalous behavior of water :: shredded ice converted into solid ice balls : Regelation
16.) Specific latent heat of vaporisation : J/Kg :: specific heat : ……………….
Answer: Specific latent heat of vaporisation : J/Kg :: specific heat : J/kg °C
17.) 2 n 1 : Refractive index of medium 1 with respect to medium 2 :: 1 n 2: ……………
Answer: 2 n 1 : Refractive index of medium 2 with respect to medium 1 :: 1 n 2: Refractive index of medium 1 with respect to medium 2
18.) Refractive index of air : 1.0003 :: refractive index of water : ……………………..
Answer: Refractive index of air : 1.0003 :: refractive index of water : 1.33
19.) Convex lens : converging :: concave lens :———-
Answer: Convex lens : converging :: concave lens : Diverging
20.) Nearsightedness: elongated eyeball :: farsightedness:———–
Answer: Nearsightedness: elongated eyeball :: farsightedness: Compression of eye ball
21.) Object at 2F1 of a convex lens : Image at 2F2 :: Object at F1 :——-
Answer: Object at 2F1 of a convex lens : Image at 2F2 :: Object at F1 : image infinity
22.) Nearsightedness : concave lense :: farsightedness :———-
Answer: Nearsightedness : concave lense :: farsightedness : Convex lense
23.) Simple microscope : Number of convex lens one :: compound microscope :———
Answer: Simple microscope : Number of convex lens one :: compound microscope : Has two convex lense.
24.) Focal length : metre :: power of lens :———
Answer: Focal length : metre :: power of lens : Dioptre
25 .) : Concave lens :: :—-
Answer: Concave lens :: :—-
26.) : Object near the lens:: :—-
Answer: Object near the lens:: :—-
27.) Brass : Aluminium and zinc : : Bronze : —————-
Answer: Brass : Aluminium and zinc : : Bronze : Copper and Tin
28.) Pressure cooker : Anodizing : : Silver plated spoons : ————–
Answer: Pressure cooker : Anodizing : : Silver plated spoons : Electroplating
29.) In Electrolytic reduction of alumina, Anode : ——- : : Cathode : Graphite lining
Answer: In Electrolytic reduction of alumina, Anode : Graphite Rods : : Cathode : Graphite lining
30.) Sulphide ores : Roasting : : Oxide ores : —————-
Answer: Sulphide ores : Roasting : : Oxide ores : Calcination
31.) Bauxite : Aluminium ore : : Cassiterite : ———–
Answer: Bauxite : Aluminium ore : : Cassiterite : Tin
32.) Metal sheets : Malleable : : Electric wires : ————
Answer: Metal sheets : Malleable : : Electric wires : Ductile
33.) Zinc sulphide : Roasting : : zinc carbonate : ————-
Answer: Zinc sulphide : Roasting : : zinc carbonate : Calcination
34.) Rusting of iron : Fe2O3 : : corrosion of copper : ———–
Answer: Rusting of iron : Fe2O3 : : corrosion of copper : CuCO3
35.) Diamond : electric insulator : :———- : electric conductor.
Answer: Diamond : electric insulator : : Graphite : electric conductor.
36.) Soft metal : Na : : hard metal :——
Answer: Soft metal : Na : : hard metal : Tungsten
37.) Aluminium:———–: gold : : electric insulator
Answer: Aluminium: Electric Conductor : gold : : electric insulator
38.) Bronze :——–:: Tin : Cu+Zn.
Answer: Bronze :——–:: Tin : Cu+Zn.
39.) Solid : iodine ::———: bromine
Answer: Solid : iodine :: Liquid : bromine
40.) CH3-CH2-CHO : propane :: CH3- COOH : ………….
Answer: CH3-CH2-CHO : propane :: CH3- COOH : Ethanoic Acid
Que 1 B)
II.) Find odd one out and give its explanation
1.) F , K , Cl , I
Answer:- k – potassium
Explanation- k belongs to 1st group of elements and all the other belongs to the halogen group i.e. 17th group
2.) Lithium, Sodium, Magnesium, Potassium
Answer :- Magnesium
Explanation :- Magnesium belongs to group 2 while other are belongs to group 1
3.) Beryllium, Helium, Neon, Argon
Answer :- Beryllium
Explanation :- Beryllium belongs to group 2 while other are belongs to group 18
4.) Gallium, Scandium, Germanium, Calcium
Answer :- Germanium
Explanation :- Germanium is a metalloid while others are metals.
5.) Boron, Arsenic, Germanium, Gallium
Answer :- gallium
Explanation :- gallium is a metal while other are metalloids
6.) Dobereiner, Newland, Mendeleev, Moseley
Answer :- Moseley
Explanation :- Moseley arranged elements in an increasing order of their atomic number whereas other arranged elements based on their atomic masses
7.) Fluorine, Boron, Bromine, Chlorine
Answer :- Boron
Explanation :- Boron is a metal while other are halogens
8.) Carbon, Calcium, Oxygen, Neon
Answer :- Calcium
Explanation :- Calcium is a metal while others are non-metals.
9.) Potassium, Magnesium, Calcium, Beryllium
Answer :- Magnesium
Explanation :- Magnesium belongs to period 3 while other are belong to period 2.
10.) Beryllium, Magnesium, Carbon, Oxygen
Answer :- Magnesium
Explanation :- Magnesium belong to period 3 while other are belongs to period 2
11.) Voltmeter, Ammeter, Galvanometer, Electric motor
Answer :- Electric motor
Explanation :- Other are used to measure electric current, voltage and electric motor is used to generate.
12.) Loud speaker, Magnet, Microphone, Electric motor
Answer :- Magnet
Explanation :- Magnet exerts a force on magnetic material while remaining three convert one form of energy into another
13.) Fuse wire, bad conductor, Rubber gloves, Generator
Answer :- Generator
Explanation: Generator is used to produce current while other are resistance to the flow of current.
14.) Tungsten, Nichrome, Aluminium, Iron
Answer:- Nichrome
Explanation:- Others are metals while nichrome is an alloy.
15.) Boiler, Electric stove, Electric bulb, Electric bell
Answer:- Boiler
Explanation:- All are electric components except the boiler hence the boiler is the correct option.
16.) Temperature, Conduction, Convection, Radiation
Answer:- Temperature
Explanation:-others are the modes of the heat of transfer except temperature because temperature is a physical quantity.
17.) cal/g, cal/g°C, Kcal/Kg°C, erg/g°C
Answer:- cal/g
Explanation:- Other three are the unit of specific heat capacity while cal/g is an unit of specific latent heat.
18.) Joule, erg, Calorie, Newton
Answer: Newton,
Explanation: Except Newton all others are unit of energy.
19.) Rainbow, Earthquake, Sunset, Sunrise
Answer: Earthquake, Earthquake is an natural disaster while others are due to the phenomenon of light.
20.) Focal length, Radius of curvature, Image distance, Size of Image
Answer: Size of Image,
Explanation: size of image is measured from perpendicular axis while Other parameters are measured from optical centre along principal axis.
21.) Simple Microscope, Compound microscope, Telescope, Prism
Answer: Prism
Explanation: All others are types of microscope except prisms.
22.) Eye lense, Retina, Cerebellum, cornea
Answer:- Cerebellum
Explanation: All others are parts of the eyes while cerebellum is a part of the brain.
23.) Object distance, Image distance, focal length, principal axis
Answer: Principal axis,
Explanation: Principal axis is not measured using scale while others are measured by using scale.
24.) Eye piece, Magnifier, Kaleidoscope, Telescope
Answer: Kaleidoscope,
Explanation: Other devices uses lenses in instrument while kaleidoscope uses mirrors.
25.) Sodium, Potassium, Silver, Sulphur
Answer: Sulphur,
Explanation: others are metals except sulphur.
26.) Boron, Chlorine, Bromine, Fluorine
Answer: Boron
Explanation : Boron is group 13 element while other are group 17.
27.) Copper, Iron, Mercury, Brass
Answer: Brass
Explanation: Other are metals while brass is an alloy.
28.) Brass, Bronze, Phosphorous, Steel
Answer: Phosphorous
Explanation: Other are alloys while phosphorous is non metal.
29.) Tinning, Alloying, Anodization, Froth floatation
Answer: Froth flotation
Explanation: Other processes are coating a thin layer of metal on the surface of other metals. While, Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic.
30.) Zinc coating, Tinning, Electroplating, Calcination
Answer: Calcination
Explanation: Other are the methods used to avoid corrosion while calcination is process involved in extraction of carbonate ores.
31.) Na, K, Cu, Li
Answer: Cu
Explanation: Other are highly reactive metals except Copper (Cu).
32.) Ethylene, Styrene, Propylene, Teflon
Answer: Teflon
Explanation: Other are monomers while Teflon is a polymer.
33.) Butane, Methane, Benzene, Ozone
Answer: Ozone
Explanation: Other are organic compounds except ozone is inorganic compounds.
34.) CH4, C2H6, C5H12 , CaCO3
Answer: CaCO3
Explanation: Other are organic compounds except CaCO3 is an inorganic compound.
35.) C2H2 , C3H8 , C2H6 , CH4
Answer: C2H2
Explanation: Except C2H2, other are saturated hydrocarbons.
36.) C2H4 , C4H10 , C3H8 , CH4
Answer: C2H4
Explanation: except C2H4, other is alkane.
37.) Sputnik, Moon, Swayam, Chandrayaan
Answer: Moon
Explanation: Except moon other are artificial satellites.
Que 1 B ) III. Answer the following questions in one sentence.
1.) Element A and B follows the Newland’s octaves rule. How many elements are there in between A and B ?
Answer:- There are eight elements in between Element A and B because Newland’s octave rule has rule that each octave contain only eight element. Hence including A and B there are total eight elements.
2.) Write the characteristic of Dobereiner’s triads?
Answer: The characteristic of Dobereiner triads is that the atomic mass of the middle element was equal to the mean of the atomic masses of the other two elements however all element does not obey Dobereiner triad.
3.) To which element does Newland’s octave rule apply?
Answer: E very eighth element has properties similar to the first element. This rule is only applicable upto calcium.
4.) Write the molecular formula of the oxide of any one of the elements in Mendeleev’s periodic table.
Answer: H2o is the molecular formula of water i.e. hydrogen oxide which is one of the element in Mendeleev’s periodic table.
5.) Write the name of noble gas having 2 electrons in its valence shell.
Answer: Helium is the noble gas element having 2 electrons in its valence shell.
6.) Write the name of an element having electronic configuration 2,8,2.
Answer: Magnesium has electronic configuration 2,8,2.
7.) Which two elements show an ambiguity regarding their sequence in Mendeleev’s periodic table?
Answer: Cobalt and Nickel shows an ambiguity regarding their sequence in Mendeleev’s periodic table.
8.) The elements beryllium, magnesium and calcium are in group 2. What will be their valency?
Answer: The elements beryllium, magnesium and calcium are in group2 hence their valency is 2.
9.) The modern periodic table is divided into which blocks?
Answer: The modern periodic table is divided into 4 blocks, S-block, P-block, d-block and f-block.
10.) What determines the chemical reactivity of elements?
Answer: the chemical reactivity of element determines the number of valence electrons in it and the shell number of the valence shell.
11.) Write chemical formula for rust.
Answer: the chemical formula for rust is Fe2 O3 X H2 O.
12.) Complete the given chemical reaction.
CuSO4 (aq)+ Fe(s) → ….. + ……
Answer: CuSO4 (aq)+ Fe(s) → FeSO4 (aq)+ Cu (s)
CuSO4 is present in aqueous form reacts with ferrous present in solid form gives the product of chemical reaction FeSO4 in aqueous form and Copper in solid form.
13.) What is the heating effect of electric current?
Answer: Heat is produced due to the current when a resistor is connected in an electrical circuit. This effect is known as heating effect of electric current.
14.) Which metal used to make the filament of an electric bulb?
Answer: Tungsten wire is used to make the filament of an electric bulb.
15.) What is a short circuit?
Answer: If we switch on the equipment in house, suddenly the electrical fuse wire get melts and electric supply shuts down. This is known as short circuit.
16.) What is the potential difference?
Answer: Potential difference is defined as the difference between potential at two charges points or bodies.
17.) How much Volts potential difference between live and neutral wires?
Answer: There is 220 Volts potential difference between live and neutral wires.
18.) What is used to turn off the sudden increase in current in the electrical circuit of the house nowadays?
Answer: Fuse wire is used to turn off the sudden increase in current in the electrical circuit of the house nowadays.
19.) Write two devices based on the heating effect of electric current.
Answer: Electric Bulb and Water boiler are the two devices based on the heating effect of electric current.
20.) Write Fleming’s right hand thumb rule.
Answer: Fleming’s right hand thumb rule gives direction of magnetic field generated by a current flowing through an electrical conductor. Imagine that you have held in right hand a conductor in such a way that the thumb indicated the direction of current. Now turn your fingers around conductor which gives the direction of the magnetic lines of force. This is known as Fleming’s right hand thumb rule.
21.) Write Fleming’s left hand rule.
Answer: Fleming’s left hand rule tell us that the direction of the force exerted is perpendicular to the direction of the magnetic field and electric field. In which left hand thumb, index finger and the middle finger are stretched in such a way that the index finger gives the direction of magnetic field, the middle finger gives the direction of current and thumb represents the direction of force on the conductor. This rule is known as Fleming’s left hand rule.
22.) Write Fleming’s right hand rule.
Answer: Place your thumb, index finger and the middle finger in such a way that they will be perpendicular to each other, in which middle finger shows the direction of induced current, the thumb shows the direction of motion of the conductor and index finger gives the direction of the magnetic field. This is known as Fleming’s left hand rule.
23.) What is a solenoid?
Answer: When a copper wire having resistive coating is wound like a spring in a chain of loops. It is known as solenoid.
24.) Write the two names in the following diagram.
A) Right hand thumb rule.
Answer:
B) Fleming’s right hand rule.
Answer:
25.) Define boiling point of a liquid.
Answer: the temperature at which the liquid gets converted into gaseous is called as boiling point of liquid.
26.) What is meant by regelation?
Answer: The phenomenon in which ice gets converted into the liquid because of applied pressure and again liquids gets converted into ice by the removal of pressure. This phenomenon is known as regelation.
27.) How fog is formed?
Answer: When the water vapour changes its state from gaseous into the liquid water droplet, fog is formed.
28.) What is a dew point temperature?
Answer: If the temperature of unsaturated air is decreased in such a way that temperature of unsaturated air is reached at which the air becomes saturated with vapour. This temperature is known as the dew point temperature.
29.) What does the existence of drops of water on the leaves of a tree in the morning indicate?
Answer: The existence of drops of water on the leaves of a tree in the morning indicates the formation of dew drops.
30.) Which temperature segment is chosen when determining the unit of heat? Why?
Answer: 14.5 ˚C to 15.5 ˚C temperature segment is chosen while determining the unit of heat.
31.) Identify the wrong figure from the following. A. B.
Answer: The wrong figure from above two is A.
32.) Write the molecular formula of the given compound.
1.) Ethyl ethanoate –
Answer: The molecular formula of Ethyle ethanoate is CH3 -COO-CH2 -CH3.
2.) Sodium ethanoate –
Answer: The molecular formula of Sodium ethanoate is CH3 COONa.
3.) Sodium ethoxide –
Answer: The molecular formula of Sodium ethoxide is CH3 -CH2 -ONa
4.) Stearic acid –
Answer: The molecular formula of Stearic acid is C17 H35 COOH.
5.) Oleic acid –
Answer: The molecular formula of Oleic acid is C17 H33 COOH.
6.) Palmitic acid –
Answer: The molecular formula of Palmitic Acid is C15 H31 COOH.
34.) Draw electron dot structure and line structure for given molecules.
1.) Hydrogen
Answer: The electron dot and line structure of hydrogen is given below:
2.) Oxygen
3.) Methane
4.) Nitrogen
5.) Ethene
Que 1 B) IV. Match the columns.
1.)
Column A |
Column B |
1. Eka- Aluminium | a. Scandium |
2. Eka- silicon | b. Gallium |
3. Eka- Boron | c. Germanium |
d. Beryllium |
Answer:
Column A |
Column B |
1. Eka- Aluminium | a. Gallium |
2. Eka- silicon | b. Germanium |
3. Eka- Boron | c. Scandium |
2.)
Column A |
Column B |
1.Triads | a. Mendeleev |
2.Octave | b. Dobereiner |
3.Atomic Number | c. Thomson |
4.Atomic Mass Number | d. Mosley |
e. Newland |
Answer:
Column A |
Column B |
1.Triads | b. Dobereiner |
2.Octave | e. Newland |
3.Atomic Number | d. Mosley |
4.Atomic Mass Number | a. Mendeleev |
3.
Column A |
Column B |
1. s-Block | a. Lanthanides And Actinides |
2. P- Block | b. Group 3 to 12 |
3. d- Block | c. Group 1,2 |
4. f-Block | d. Group 13 to 18 |
e. Zero Group |
Answer:
Column A |
Column B |
1. s-Block | c. Group 1,2 |
2. P- Block | d. Group 13 to 18 |
3. d- Block | b. Group 3 to 12 |
4. f-Block | a. Lanthanides And Actinides |
4.)
Column A |
Column B |
Electronic configuration | Valency |
1. 2,2 | a. 1 |
2. 2,8,1 | b. 2 |
3. 2,5 | c. 3 |
4. 5 |
Answer :
Column A | Column B |
Electronic configuration | Valency |
1. 2,2 | b. 2 |
2. 2,8,1 | a. 1 |
3. 2,5 | c. 3 |
4. 5 |
5.
Column A |
Column B |
1. Alkaline earth metals | a. Group 18 |
2.Alkali metals | b. Group 17 |
3.Halogen | c. Group 2 |
4.Noble gas | d. Group 1 |
e. Group 14 |
Answer:
Column A |
Column B |
1. Alkaline earth metals | c. Group 2 |
2.Alkali metals | d. Group 1 |
3.Halogen | b. Group 17 |
4.Noble gas | a. Group 18 |
6.)
Column A |
Column B |
1) Direct Current | a. Oscillatory |
2) Alternating Current | b. Non oscillatory |
Answer:
Column A |
Column B |
1) Direct Current | b. Non oscillatory |
2) Alternating Current | a. Oscillatory |
7.)
Column A |
Column B |
1. specific latent heat of fusion | a. Air Saturated with vapour |
2. Specific latent heat of vaporisation | b. Solid converts into Liquid |
3. Dew point temperature | c. Liquid converts into gas |
Answer:
Column A |
Column B |
1. specific latent heat of fusion | b. Solid converts into Liquid |
2. Specific latent heat of vaporisation | c. Liquid converts into gas |
3. Dew point temperature | a. Air Saturated with vapour |
8.)
Column A |
Column B |
1. Absolute humidity | a) J/cal |
2.Latent heat | b) J/Kg° C |
3.Specific Heat capacity | c) KJ/Kg |
4.Heat | d) no unit |
e) Kg/m3 |
Answer:
Column A |
Column B |
1. Absolute humidity | e) Kg/m3 |
2.Latent heat | c) KJ/Kg |
3.Specific Heat capacity | b) J/Kg° C |
4.Heat | a) J/cal |
9.)
Column A |
Column B |
1) Dry air | a) 4°C |
2) Humid air | b) Relative humidity 100% |
3) Saturated air/Dew point temperature | c) Relative humidity below 60% |
4) Maximum density of water | d) Relative humidity above 60% |
e) -4°C |
Answer:
Column A |
Column B |
1) Dry air | c) Relative humidity below 60% |
2) Humid air | d) Relative humidity above 60% |
3) Saturated air/Dew point temperature | b) Relative humidity 100% |
4) Maximum density of water | a) 4°C |
10.)
Substance |
Property |
1) KBr | a) Combustible |
2) Neon | b) Soluble in water |
3) Gold | c) No chemical reaction |
4) Sulphur | d) High ductility |
Answer:
Substance |
Property |
1) KBr | b. soluble in water |
2) Neon | c) No chemical reaction |
3) Gold | d) High ductility |
4) Sulphur | a) Combustible |
11.)
Group A |
Group B |
1.Bauxite | a) Mercury |
2.Cassiterite | b) Aluminium |
3.Cinnabar | c) Tin |
Answer:
Group A |
Group B |
1.Bauxite | b) Aluminium |
2.Cassiterite | c) Tin |
3.Cinnabar | a) Mercury |
12.)
Group A |
Group B |
1. ZnS | a) Copper Sulphide |
2. HgS | b) Bauxite |
c) Cinnabar | |
d) Zinc blend |
Answer:
Group A |
Group B |
1. ZnS | d) Zinc blend |
2. HgS | c) Cinnabar |
13.)
Group A |
Group B |
1. Copper and Zinc | a. Brass |
2. Copper and Tin | b. Steel |
c. Stainless steel |
Answer:
Group A |
Group B |
1. Copper and Zinc | a. Brass |
2. Copper and Tin | b. Steel |
14.)
Group A |
Group B |
1. Electroplating | a. Pressure cooker |
2. Anodising | b. Silver plated spoons |
c. Coating of tin on copper | |
d. Coating of zinc on iron |
Answer:
Group A | Group B |
1. Electroplating | b. Silver plated spoons |
2. Anodising | a. Pressure cooker |
15.)
Group A |
Group B |
1. Making sheets of metals | a. Sonority |
2. Making metal utensils | b. Malleability |
3. Making copper wires | c. Good conductor of heat |
4. Making bells from metak | d. Ductility |
Answer:
Group A |
Group B |
1. Making sheets of metals | b. Malleability |
2. Making metal utensils | c. Good conductor of heat |
3. Making copper wires | d. Ductility |
4. Making bells from metak | a. Sonority |
16.)
Group A |
Group B |
1) C2H6 | a) Unsaturated hydrocarbons |
2) C2H2 | b) Molecular formula of one alcohol |
3) CH4O | c) Saturated hydrocarbons |
4) C3H6 | d) Triple bond |
Answer:
Group A |
Group B |
1) C2H6 | a) saturated hydrocarbons |
2) C2H2 | b) Triple bond |
3) CH4O | c) Molecular formula of one alcohol |
4) C3H6 | d) unsaturated hydrocarbons |
17.)
Group A |
Group B |
1 Straight chain hydrocarbon | a) Benzene |
2 Branched chain hydrocarbon | b) Propyne |
3 Cyclic hydrocarbon | c) Isobutylene |
Answer:
Group A |
Group B |
1 Straight chain hydrocarbon | b) Propyne |
2 Branched chain hydrocarbon | c) Isobutylene |
3 Cyclic hydrocarbon | a) Benzene |
18.)
Group A |
Group B |
1. Ether | a) –OH |
2. Kitone | b) –O- |
3. Ester | c) –CO- |
4. Alcohol | d) –COO- |
Answer:
Group A |
Group B |
1. Ether | b) –O- |
2. Kitone | c) –CO- |
3. Ester | d) –COO- |
4. Alcohol | a) –OH |
Que. 1 B) V. Complete the incomplete sentence.
1.) According to Newland’s octave rule, chlorine shows similarity with fluorine. Because, chlorine is
Answer: According to Newland’s octave rule, chlorine shows similarity with fluorine. Because, chlorine is eighth element to the florine.
2.) According to Mendeleev’s periodic law properties of elements are …..
Answer: According to Mendeleev’s periodic law properties of elements are periodic function of their atomic masses.
3.) The number of electrons in the outermost shell of an atom determines the ___.
Answer: The number of electrons in the outermost shell of an atom determines the Valency.
4.) Electropositivity means __________.
Answer: Electropositivity means tendency of an element to form a cation by losing its valence electron.
5.) According to Dobereiner’s triads rule, three elements in an increasing order of atomic mass shows ___________.
Answer: According to Dobereiner’s triads rule, three elements in an increasing order of atomic mass shows that the atomic mass of middle element is approximately equal to the mean of the atomic masses of the other two elements.
Que.1B) VI. Write the name:
1.) The atom having the biggest atomic size from period 2.
Answer: The atom having the biggest atomic size from period 2 is Lithium.
2.) The atom having the smallest atomic radius from zero group.
Answer: The atom having the smallest atomic radius from zero group is Helium
3.) The family of group 1 elements.
Answer: The family of group 1 elements is Alkali metals.
4.) Highest reactive non metal.
Answer: Highest reactive non metal is Flourine.
5.) The element having stable electron configuration from the third period.
Answer: The element having stable electron configuration from the third period is Argon.
6.) A halogen from period 4.
Answer: A halogen from period 4 is Bromine.
7.) The family of elements having zero valency.
Answer: The family of elements having zero valency is noble gases/ inert gases.
8.) Two elements having two orbits.
Answer: Two element having two orbits are carbon and oxygen.
9.) Highest electronegative element
Answer: Highest electronegative elements are carbon, nitrogen, fluorine, oxygen.
10.) Highest electropositive element .
Answer: The highest electropositive element is Zinc
11.) The atom having smallest atomic radius from group 1.
Answer: The atom having smallest atomic radius from group 1 is hydrogen
12.) The group of elements having electronic configuration 2, 2.
Answer The group of elements having electronic configuration 2,2 is beryllium.
13.) Product obtained when sugar is heated.
Answer: Carbon and water vapour obtained when sugar is heated.
14.) The phase in which solid substances are converted into liquid – melting.
Answer: In melting phase solid substances are converted into liquid.
15.) The amount of heat absorbed at constant temperature by unit mass of a liquid to convert into gaseous phase.
Answer: The amount of heat absorbed at constant temperature by unit mass of a liquid to convert into gaseous phase is known as specific latent heat of vaporization.
16.) Conversion of ice into liquid due to applied pressure and the reconverts to ice once the pressure is removed –
Answer: Conversion of ice into liquid due to applied pressure and the reconverts to ice once the pressure is removed is known as regelation
17.) The instrument used to study anomalous behaviour of water.
Answer: The instrument used to study anomalous behaviour of water is Hope’s apparatus.
18.) The instrument used to measure the specific heat capacity of a substance using mixture method.
Answer: The instrument used to measure the specific heat capacity of a substance using mixture method is Calorimeter.
19.) The distance between focus and optical centre.
Answer: The distance between focus and optical centre is called as focal length.
20.) The part of human eye that transmits electrical signals to the brain.
Answer: The part of human eye that transmits electrical signals to the brain is Retina.
21.) The lens used in simple microscope.
Answer: The lens used in simple microscope is convex lense.
22.) The ability of lens to adjust the focal length as per need is –
Answer: The ability of lens to adjust the focal length as per need is the power of accommodation.
23.) The defect of eye occurring due to ageing.
Answer: The defect of eye occurring due to ageing is Prespbyopia
24.) The fleshy screen behind cornea.
Answer: The fleshy screen behind cornea is Iris.
25.) The screen with light sensitive cells in human eye
Answer: The screen with light sensitive cells in human eye is Retina.
26.) The sensation on the retina persists for a while is
Answer: The sensation on the retina persists for a while is Persistence of vision.
27.) The persons which are unable to distinguish between different colours
Answer: The persons which are unable to distinguish between different colours is Colour Blind
28.) The imaginary line passing through two optical centers of lens.
Answer: The imaginary line passing through two optical centres of lens is called Principle axis.
29.) The molecular formula of main ore of aluminium
Answer: The molecular formula of main ore of aluminium is Al2o3.2H2O
30.) The ore is produced by using –
Answer: The ore is produced by using Smelting.
31.) Non-metals which are good conductors.
Answer: The graphite is non-metal which is a good conductor.
32.) The reagent which dissolves noble metals.
Answer: The reagent which dissolves noble metals is Aqua Regia.
33.) Metals which are amphoteric in nature
Answer: Metals which are amphoteric is nature are Aluminium and Zinc
34.) An alloy of copper and zinc.
Answer: An alloy of copper and zinc is Brass.
35.) Two highly reactive metals
Answer: Two highly reactive metals are sodium and magnesium.
36.) Strongly heating carbonates ores in insufficient air.
Answer: Strongly heating carbonates ores in insufficient air is calcination.
37.) Extraction of aluminium from alumina-
Answer: Extraction of aluminium from alumina is Electrolytic reduction of Alumina.
38.) Method used to present corrosion of copper.
Answer: Method used to present corrosion of copper is Tinning.
Question 1 . B) Right or wrong sentence.
1.) If the distance between two masses is doubled, the gravitational force between them becomes less than the previous force.
Answer: Right
2.) The CGS unit of G is dyne.cm 2/g 2 .
Answer:- Right
3.) The value of gravitational acceleration with the center of the earth is zero.
Answer:-Right
4.) The value of g is highest at the equator.
Answer:- Wrong, the value of g is highest at the poles.
5.) The value of G varies from place to place.
Answer:-Right
6.) As it rises above the earth’s surface, its value increases.
Answer: Wrong, as it rises above the earth’s surface, its value decreases.
7.) The speed of release of an object does not depend on the mass of the object.
Answer: Right
8.) Mass is a qualitative measure of the inertia of an object.
Answer:- Right
9.) The similarity between the properties of the first and eighth elements is called the octave rule.
Answer:- Right
10.) In Dobreiner’s triangles, three elements appear to be arranged in ascending order of their atoms.
Answer:- Right
11.) While designing the periodic table, Mendeleev considered the chemical and physical properties of the elements.
Answer: Right
12.) The modern periodic table has 1 to 7 cycles.
Answer: Right
13.) The modern periodic table shows the molecular values of the elements in each frame.
Answer: Wrong, the modern periodic table shows the atomic numbers of the elements in each frame.
14.) P-segment is composed of groups 1 and 2.
Answer: Right
15.) To the left of the serpentine line in the periodic table are the metal elements.
Answer: Right
16.) The compound of the elements in group 2 is 1.
Answer: Wrong , the compound of the element is group 2 is 2.
17.) Nanometers use these units to measure atoms.
Answer: Wrong, The atomic mass unit (amu) is used to measure atoms.
18.) Moving from left to right, the size of the atom decreases.
Answer: Right
19.) All the elements in the halogen family are gases.
Answer: Wrong, all the elements in the halogen family are not gases.
20.) The elements lithium and beryllium are in the same cycle because their compounds are similar.
Answer: Wrong, The element lithium and beryllium are in the same cycle because their chemical properties are similar.
21.) Beryllium and calcium are alkaline soil metals.
Answer: Right
22.) The K and L shells of the elements Na and Mg contain electrons.
Answer: Right
23.) The number of shields decreases as the calculation goes down from top to bottom.
Answer: Wrong, the number of shells increases as the calculation goes down from top to bottom.
24.) The metal properties of the element decrease as the spiral moves from left to right.
Answer: Right
25.) The size of an atom depends on the number of compound electrons.
Answer: Wrong, the size of atom depends on its atomic radii.
26.) Silicon is a metallic element.
Answer: Wrong, Silicon is an metalloid.
27.) The properties of the metal increase as it goes down in the calculation.
Answer: Right
28.) Electrical negativity is the metallic property of an element.
Answer: Wrong, electrical negativity is non-metallic property of an element.
29.) If edible oil is kept well for a long time, it will get sour.
Answer: Right
30.) The alternating current is a vibrating current.
Answer: Right
31.) Electrical wires and neutral wires have a 220 V potential difference.
Answer: Wrong, The neutral wire have 0V and electrical wire has 220V.
32.) Increasing the current passing through the wire decreases the magnetic field intensity.
Answer: Wrong , increasing the current passing through the wire does not affect the magnetic field intensity.
33.) Use galvanometers for electrical measurements.
Answer: Right
34.) The frequency of the alternating current is 50Hz.
Answer: Right
35.) Electrochemicals are devices that convert electrical energy into mechanical energy.
Answer: Right
36.) The dew point temperature does not depend on the amount of vapor in the air.
Answer: Wrong, The dew point temperature depends on the amount of vapour in the air.
37.) The specific heat capacity of water is 1 cal / g 0C.
Answer: Right
38.) The invisible heat of evaporation is called the conversion of gas into liquid.
Answer: Wrong, The invisible heat of evaporation is called the condensation.
39.) Use calorimeters to study the inconsistent behavior of water.
Answer: Wrong, Calorimeter is used to study specific heat capacity.
40.) During reheating, ice is converted to water at a temperature of 0°C.
Answer: Right
41.) 1 kg of dry air at a temperature of 40 °C can hold a maximum of 49 g of water vapor.
Answer: Right
42.) Calorimeters are used to measure specific calorific value.
Answer: Right
43.) All metals have the same specific heat capacity.
Answer: Wrong, all metals have different specific heat capacity.
44.) Humidity relative to dew point temperature is 100%.
Answer: Right
45.) The unit of absolute humidity is Kg / m 3 .
Answer: Right
46.) 1 calorie is 4.81 joules
Answer: Wrong, 1 calorie = 4.184 Joules
47.) The incident rays and refracting rays are on opposite sides of the column.
Answer: Right
48.) Purple has the lowest refractive index.
Answer: Wrong, red colour has lowest refractive index.
49.) The speed of light varies in different media.
Answer: Right
50.) Convex magnifying glass is called divergent magnifying glass and concave magnifying glass is called converging magnifying glass.
Answer; Wrong, convex magnifying glass is called converging, and concave magnifying glass is called diverging.
51.) The image of the object in the human eye is formed on the cross screen.
Answer; Wrong, image of the object in the human eye is formed on the retina.
52.) This defect of vision can be remedied by using endoscopic magnifying glass with proper focal length.
Answer: Right
53.) If the incident ray is parallel to the main axis, then the refracted ray passes through the main navel.
Answer: Right
54.) The image of an object at an infinite distance is obtained in a real and smooth form through a convex magnifying glass.
Answer: Wrong
55.) The power of the magnifying glass depends on the distance of the magnifying glass.
Answer: Wrong, the power of magnifying glass depends on the distance between eye of person and object.
56.) The lens of the eye is flattened when looking at nearby objects.
Answer: Wrong, the lens of the eye is flattened when looking at far object.
57.) For a healthy human eye the distant point is infinite distance.
Answer: Right
58.) Vision defects increase the distance between the lens of the eye and the retina of the eye. There are defects in myopia.
Answer: Right
59.) The virtual shape of the object seen by the eye depends on the angle held by the object with the eye.
Answer: Right
60.) Electrolysis is used to obtain pure metal from impure metal.
Answer: Right
61.) Ionic compounds are soluble in kerosene.
Answer: Wrong
62.) Stable ionic compounds conduct electricity.
Answer: Wrong, stable ionic compounds do not conduct electricity.
63.) Mercury, silver, gold are highly reactive metals.
Answer: Wrong, mercury silver and gold are less reactive metals.
64.) In the electrolytic method, a layer of highly active metal is applied to a less active metal.
Answer: Wrong, in electrolytic method, a layer of less active metal is applied to a high active metal.
65.) In the electrolytic dissipation method of alumina, the lining of graphite acts as an anode.
Answer: Right
66.) The electrolysis of alumina combines fluospar and cryolite to increase the solubility in the precipitation method.
Answer: Wrong, the electrolysis of alumina combines fluorspar and cryolite to decrease the solubility in the precipitation method.
67.) Cassiteite is a copper metal.
Answer: Wrong, Cassiteite is a copper ore.
68.) Diamond is a hard substance.
Answer: Wrong, Electrons of diamond are shared with four carbon atoms to form a strong chemical bond which in turn forms tetrahedral crystal which makes diamond a hard substance.
69.) Gold and silver are active metals.
Answer: Wrong, gold and silver do not react with water, air and acid hence they are less active metals.
70.) Halogen reacts with acid.
Answer: Right
71.) Baux reacts with sodium hydroxide in the Bayer process.
Answer: Right
72.) The number of electrons in the compound shell of a carbon atom is 4.
Answer: Right
73.) Your body is made up of carbon.
Answer: Right
74.) Carbon compounds contain only free chains of carbon atoms.
Answer: Wrong, Carbon compounds contain continuous chain of carbon atoms.
75.) Two carbon atoms can always form one or two covalent bonds.
Answer: Wrong, two carbon atoms can form one covalent bond.
76.) In general, saturated compounds are more reactive than unsaturated compounds.
Answer: Wrong, Unsaturated compounds are more reactive than saturated.
77.) Benzene is a coated unsaturated hydrocarbon.
Answer: Right
78.) Cyclohexane is a branched chain type of hydrocarbon.
Answer: Wrong, cyclohexane is a cyclic branched chain type of hydrocarbon.
79.) As one ascends in any homogeneous category, physical properties change in one direction.
Answer: Right
80.) There are different common molecules for all members of the homologous range.
Answer: Wrong, member of homologous series has different number of CH2 groups.
81.) LPG Butane is a flammable element in.
Answer: Right
82.) Substances that can give oxygen to other substances are called particulate matter.
Answer: Wrong, substance that can give oxygen to other substances are called oxidation.
83.) Potassium permanganate is an oxidizing compound in regular use.
Answer: Right
84.) Colorless ethanol is in liquid state at room temperature.
Answer: Right
85.) Ethanol is all soluble in water.
Answer: Right
86.) Easter is a sweet-smelling dish.
Answer: Right
87.) The speed of liberation on the moon is less than the speed of liberation on earth.
Answer: Right
88.) India is the first country to discover the existence of water on the moon.
Answer: Right
89.) The function of a satellite launcher is based on Newton’s second law of motion.
Answer: Right
Question 1 (B) VIII. Write an explanation.
1.) Group
Answer: According to modern periodic table, the vertical columns in the periodic table are called groups. These are eighteen vertical columns named Group 1 to Group 18. The complete periodic table is split up into four blocks as p-block, s-block, d-block and f-block. Group 1 and group 2ew are in s-block, group 13 to group 18 constitute p-block, group 3 to group12 constitute d-block and lanthanide and actinide series constitute f-block. Element in the same group shows similar properties and gradation. The electronic configuration of the element decides the group of element in which element is to be placed. Depending on the number of valence electron in the outermost shell of the element, the group 1 is known for family of alkali metals, group 2 is known for family of alkaline earth metals, group 17 is known for the family of halogens. The electronic configuration of the outermost shell is the characteristic of a specific group. The atomic size of the element goes on increasing down the group because the new shell is added. Going down the group metallic characteristics of element increases.
2.) Period
Answer: The horizontal rows in the periodic table are known as Periods. The modern periodic table consist of seven periods. The characteristics of periods in the modern periodic table are due to the electronic configuration of element. The properties of elements change gradually while going from left to right in specific period. The electronic configuration decides the period in which element is to be placed. In periods, the number of valence electrons is different in elements with the same number of shells. It is said that the element with the same number of shells filled by electrons belongs to the same period. For example, the elements of second periods have electrons in the two shells, k and L while the elements of third periods have electrons in the three shells i.e. K, L and M. In first three periods the number of electrons is determined by the electron capacity of the shell and according to the law of electron octet. Atomic radius goes on decreasing from left to right within a period while atomic number increases by one. While going from left to right within any period electronegativity of element increases while electropositivity decreases.
3.) Atomic radius
Answer: The size of any atom is expressed by its radius. Atomic radius is defined as the distance between the nucleus and outermost shell of the atom. It is measured in picometer (1pm = 10^-12m). It has been predicted that the atomic radius of atom goes on decreasing from left to right within a period because the atomic number increases by one results in increase of positive charge and that additional electron gets added in the same outermost shell, due to increase in nuclear charge the electrons get attracted toward the nucleus and thereby the size of the atom decrease. Atomic size increases down the group.
4.) Electropositivity
Answer: By comparing the properties of metals and non-metals. It is seen that the cation in the compounds is formed from metal and anion from a non-metal hence the metal atom have a tendency to form a cation by losing its valence electron, this property of metal atoms is called as electropositivity. Electrons in the atom are held by the attractive force by the positively charged nucleus on electrons. Electrons lies in inner shell in between valence shell and the nucleus. Due to the presence of valence shell and nucleus the attractive force on electron is somewhat less than the actual nuclear charge. Thus, the number of valence electron in metals is small and the effective nuclear charge is also small and hence the combined effect of these two the metals carried a tendency to lose valence electron to form cations. This tendency of an element called electropositivity. The metallic character of an atom is its tendency to lose electron and the metallic character of element increases as going down the group and hence the electropositivity increases down the group. Within a period, going from left to right the electropositivity of metals goes on decreasing.
5.) Electronegativity
Answer: Electronegativity is the tendency of elements to form a anion by attacting the shared electron. It is an ability of an atom to become anion by accepting outside electron. Going from left to right within a period the valence electrons are held with the greater attractive force due to which the ability of an atom to accept electron from outside increases. Electronegativity is the non-metallic character of an element. Down the group the electronegativity goes on decreasing while going from left to right within a period electronegativity of element goes on increasing. Large electronegativity of element results in the higher reactivity of element.
6.) Balanced equations
Answer: If the number of atoms of the element in the reactants is same as the number of atoms of those elements in the product. Such type of equation is called a balanced equation. A chemical equation is balanced step by step. A Trial and error method us used to balance a chemical equation. In other way a balanced equation is obtained from unbalanced equation by applying proper factors to specific reactant/ product so as to balance the no of elements in steps.
7.) Endothermic reaction
Answer: The chemical reaction in which the heat is either absorbed. In this reaction heat is absorbed from the surrounding. The process of absorbing heat from the surrounding is known as endothermic process.
8.) Critical angle
Answer: When the value of angle of reflection is equal to 90 for a particular value of i (Angle of incidence). This angle is known as Critical Angle. If the angle of incidence is greater than the critical angle, the angle of reflection is also greater than 90 degree.
9.) Center of curvature of the Lense
Answer: The centre of sphere that forms the lens is called centre of curvature. Convex lenses and concave lense are formed by the part of spheres. Hence it has two centres of curvature.
10.) The optical center of the lens :-
Answer: It is defined as the point on the principal axis of the lens passes through the rays of light without any distraction or deflection.
11.) Principal focus :-
Answer: Incident a ray of light which is parallel to the principal axis on the convex lens, the rays get converged on the a point of the principal axis that point is called as principal focus. Convex lens has two principal foci f1 and f2.
12.) Focal length :-
Answer: For a curved mirror it is a distance between optical centre O and the principal focus F of the lens. It is denoted by f.
13.) Principal axis
Answer: An imaginary axis that passes through the centre of sphere which parts the lens into two equal parts is called as principal axis.
14.) Minimum Distance of distinct vision
Answer: The short distance from the normal eye to an object, at which the object is clearly visible to the eye without any straining the eye. This is known as the minimum distance of distinct vision. For the object nearer to the normal eye, the distance is 25 cm.
15.) Farthest Distance of distinct vision
Answer: When an object is kept at the farthest distance and still clearly visible to normal eye, that farthest distance between the normal eye and the object is called as farthest distance of distinct vision. The distance of normal eye for the farthest distance vision is at infinity.
16.) Magnification :
Answer: Magnification occurs due to the effect of lens. It is a ratio of height of an image to the height of the object. It is denoted by M. The formula for the magnification is given as
Magnification = Height of the Image /Height of the object.
17.) Power of accommodation
Answer: The power of accommodation is the ability to clearly focus on near and far objects on the retina by adjusting the focal length of the lens of the eye.
18.) Persistence of vision :
Answer: — When the object is removed in front of eye still image remains imprinted on retina for 1/16th of second. This sensation persists for a while on retina. This is called persistence of vision.
19.) Alkane:
Answer: Alkane are the saturated hydrocarbons in which the valencies of all the atoms in compounds are satisfied by the single bond. Alkane consists of hydrogen and carbon atoms.
20.) Alkene :
Answer: Alkene are the unsaturated hydrocarbons which contains the carbon-carbon double bonds. Unsaturated hydrocarbons contain double or triple bond between two carbon atoms. Ethene is the example of Alkene.
21.) Alkyne :
Answer: Alkyne are the unsaturated hydrocarbons which contains the carbon-carbon triple bond and are more reactive than the saturated compounds. Ethyne and ethane are the unsaturated hydrocarbons because they have double or triple bond between two carbon atoms. Ethyne is the example of alkyne,
Q1B IX. Identify who I am!
1.) Carbon aberrations ————–
Answer:- Diamond , Graphite and Fullerenes.
2.) Mutual oxide forming metal ———
Answer: Aluminium Oxide
3.) Ores of Aluminum ————
Answer: Bauxite
4.) Metal in Liquid state ——————
Answer: Mercury
Question 2 (A) Write Scientific reasons. (2 marks each)
1.) The value of acceleration g is greater at the pole than at the equator.
Answer: The value of acceleration g is greater at the pole than at the equator because of the shape of the earth. The shape of earth is bulged at equator and flattened at poles due to which the radius of earth vary. The radius of earth is less at the poles than equator. According to the relation between radius and acceleration due to gravity it is found that the acceleration due to gravity increases with decrease in radius and hence the value of g is greater at poles than equator.
2.) The value of gravitational acceleration (g) decreases as we go above the Earth’s surface.
Answer: Above the earth surface distance between object and earth increases. The value of g is inversely proportional to the r2 and hence as the distance increases above the earth surface acceleration due to gravity decreases.
3.) The value of gravitational acceleration (g) decreases as we go deep inside the earth.
Answer: The value of gravitational acceleration depends on the Mass of the earth and the radius of earth. As we go deep inside the earth the value of R and M changes and hence the value of g also decreases.
4.) When we drop a feather and a stone at the same time from a height the stone reach the earth faster than a feather.
Answer: When the object falls from some height it experiences the force due to the buoyancy of air in the upward direction. This opposition due to the air depends on the size, shape, density and velocity of the body. Hence the stone has greater acceleration in downward direction as compare to the feather. Therefore stone reaches the earth faster than a feather.
5.) The weight of an object varies on different planets.
Answer: The weight of an object of mass m on the surface of planet of mass M and planet of radius is given by W = GmM/R^2. For a given body its mass m and the value of G is constant but the Mass of planet and Radius of planet varies from planet to planet and hence the ratio GmM/R62 is different. Therefore The weight of an object varies on different planets.
6.) The value of gravitational acceleration (g) is taken to be -g when studying the motion of an object thrown upwards in a straight line.
Answer: If we thrown any object in upward direction, the acceleration due to gravity acts on object in opposite direction to the velocity of object and hence the value of gravitational acceleration is considered to be negative when studying the motion of an object thrown upwards in a straight line.
7.) The value of g at the center of the earth is zero.
Answer: The value of g on the surface of earth depends on the mass M of earth and the radius of the earth. If we go inside the earth, our distance goes on decreasing from the contre of earth. The value of M also decreases due to the effect of gravitational force. Due to the combined effect of Mass of earth M and the radius of earth, the value of g becomes zero at the centre of the earth.
8.) Mendeleev kept vacant places in the periodic table.
Answer: Mendeleev arranged the elements in the periodic table on the basis of their chemical and physical properties. Some elements were not discovered till then. Hence Mendeleev kept vacant places in the periodic table.
9.) There was ambiguity about the correct position of hydrogen in Mendeleev’s periodic table.
Answer: Hydrogen shown the unique behaviour. There was confusion in the position of hydrogen whether it is in group of alkali metals or in the group of halogens. Hence there was ambiguity about the correct position of hydrogen in Mendeleev’s periodic table.
10.) Boron and oxygen elements are placed in the second period in periodic table.
Answer: The elements having same number of shells occupied by the electrons belongs to the same period. Boron and Oxygen both contains their electrons in K and L shell and hence Boron and Oxygen elements are placed in the second period in periodic table.
11.) There was no definitive place for isotope in Mendeleev’s periodic table.
Answer: isotopes have same chemical properties but different atomic mass. Isotopes were not discovered at the time of Mendeleev’s predictions. Thus there was no definitive place for isotopes in Mendeleev’s periodic table.
12.) Lithium and sodium are included in the same group in periodic table.
Answer: Lithium and sodium have same number of valency. Element belonging to the same group have same valency. Hence lithium and sodium are included in the same group in periodic table.
13.) In same period’s boron and oxygen elements have different atomic size.
Answer: Within periods, electron gets added in the outermost shell due to which effective nuclear charge increases. Thus electrons get attracted to the nucleus which decreases the size of oxygen atom. Hence the Boron and oxygen in same period have different atomic size.
14.) The metallic character of elements increases while going down the groups.
Answer: Metallic character is the tendency to lose electron to form cation. Down the group new shell added which in turn results in increase of distance between nucleus and electron.
15.) The non-metallic character increasing while going from left to right in a period.
Answer: Non-metallic character is the capacity of an element to produce anion or to generate electronegativity. While going from left to right in a period the electronegativity of element goes on increasing due to which the tendency of atom to form anion also increases and hence the non-metallic character also increases.
16.) In a group , the size of the atom increases as it goes down from the top.
Answer: The size of the atom is given by its radius. While going down the group new shell get added and the distance between nucleus and the outermost shell electron goes on increasing. Thus the atomic radius of goes on increasing down the group.
17.) In group 2, beryllium and calcium elements, calcium is the most electropositive element than beryllium.
Answer: Calcium loses its electron more reactively than beryllium and hence calcium is most electropositive element than beryllium in group 2.
18.) Elements belonging to the same group have the same valency.
Answer: The number of electrons in the outermost shell of an atom of element are same in number and hence the elements belonging to the same group have the same valency.
19.) Always Paints door and windows before using their nets.
Answer: To prevent the rusting of iron door and iron windows by the surrounding air, water doors and windows are painted before using.
20.) It is recommended to use air tight container for storing oil for long time.
Answer: To avoid the oxidation reaction of oil also to avoid the rancidity it is recommended to use air tight container for storing oil for long time.
21.) When the gas formed heating the limestone is passed through the freshly prepared lime water, the lime water turns milky.
Answer: By heating limestone, the carbon dioxide gas and calcium carbonate is formed. On passing this carbon dioxide gas through freshly prepared lime water, the insoluble calcium carbonate and water formed. In this way lime water turns milky.
22.) It takes time for pieces of Shahabadi tile to disappear in HCl but it’s powder disappears rapidly.
Answer: Smaller the size of reactant, the faster is the rate of reaction. Thus the rate of reaction depends on the size of particle of reactant. When a piece of Shahabadi tile reacts with the dil. Hcl it forms CO2 gas slowly and tiles get disappeared gradually. If the powdered shahabadi tile reacts with the dil Hcl CO2 gas released fastly and hence the powdered tile get disappear rapidly.
23.) In practice the unit of kWh is used for the measurement of electrical energy, rather than Joule.
Answer: It is more convenient to use Kwh instead of Joule to express the measurement of electrical energy because the joule is the smallest unit for the measurement high generated electrical energy and it is hard to measure the electrical energy. 1 kwh = 3.6 x 106 J. Therefore in practice the unit of Kwh is used for the measurement of electrical energy rather than Joule.
24.) Tungsten metal is used to make a solenoid type coil in an electric bulbs.
Answer: Due to the heating effect of current, the tungsten metal get heated when an electric current pass through it and hence emits the light. Thus Tungsten metal is used to make a solenoid type coil in an electric bulb.
25.) For electric power transmission , Copper or aluminum wires is used.
Answer: Copper and aluminium have low resistivity because they are good conductors of electricity. On passing a current through the copper and aluminium wire, it produces heat in fewer amounts. Therefore for the electric power transmission, copper or aluminium wires are used.
26.) Nowadays MCBs are used in homes, for stop the current in the circuit which suddenly increases .
Answer: When we use huge electrical power, excessive electrical current is drawn out by the transformer providing electricity and if transformer with the insufficient capacity is used in device, the fuse wire in it melts and the power get shutdown. And hence to avoid the overloading due to the excessive current flow MCB’s are used in homes.
27.) A coil made up of alloy Nichrome is used in the electric heater-cooker as a resistor.
Answer: The electric heater-cooker works on the principle of heating effect of current. When the electric current passed through the circuit it produces heat. The coil made up of alloy like Nichrome has high resistivity and due to which it produces high temperature.
28.) It is beneficial to carry electrical energy in reverse form as it is carried over long distances.
Answer: When the electrical energy carried in reverse or AC form it causes minimum power loss and hence it is beneficial to carry electrical energy in reverse form as it is carried over long distances.
29.) In cold regions, in winter the pipes for water supply breaks .
Answer: Due to the anomalous behaviour or expansion of water the pipes of water supply breaks. In winter the temperature of water goes on decreasing and at one point the water get expand and due to this pipes in winter breaks.
30.) Even if boiling water is constantly heated, its temperature does not rise.
Answer: The heat we supplied to boiling water is used to convert state of water from liquid to gaseous state hence even if boiling water is constantly heated, its temperature does not rise.
31.) Use a pressure cooker to cook food in cold air.
Answer: In cold air more heat is needed for cooking food. Pressure cooker produces more heat inside the cooker which increases the boiling point inside the cooker which help to cook food more quickly.
32.) In the cold regions, snow falls in winter.
Answer: Due to the low temperature water vapours present in environment freezes and mixed with the smoke or any other dust particles which forms ice crystals. When these ice crystals combine with other particles, it get heavier and falls on the ground.
33.) The bottom of some steel utensils used for cooking is copper.
Answer: Copper conducts more heat because of its property of being good conductor of heat. Copper heated more fast as compare to steel and hence to reduce cooking time and fuel the bottom of some utensils used for cooking is copper.
34.) Drops of water can be seen accumulating on the glass of vehicles in the early hours of winter.
Answer: Due to the formation of dews on the surface of glass in early morning due to the condensation of vapour, water droplets can be seen accumulating on the glass of vehicles.
35.) During winter season, we may have observed a white trail at the back of flying high in the clear sky or sometimes it may not get formed.
Answer: The appearance of white trail and disappearance of white trail depends on the relative humidity of the air present in surrounding. If the relative humidity of air is high, white trail appears in the sky and if the relative humidity of air in surrounding is low, white trail may not appear in the sky.
36.) Fish can survive even in frozen ponds in cold regions.
Answer: There is no heat exchange between atmosphere and the water in ponds because ice does not conduct electricity. And hence fish can survive even in frozen ponds in clod regions.
37.) Placing a plastic bottle filled with water in the freezing compartment in the freezer can cause the bottle to explode.
Answer: Due to the anomalous behaviour of water, the water inside the bottle freezes at as the temperature of water reaches to 4 degree c. At this temperature water starts expanding and hence the bottle explodes.
38.) Even the wire moves through the ice slab, the ice slab does not break.
Answer: The ice slab exerts pressure due to which it melts and wire passes out with the water. once the wire passes from slab the water again refreezes and continues this process.
39.) The sun appears on the western horizon for some time after sunset.
Answer: The rays coming from the sun when incidence, due to the refraction the sun appears on the western horizon for some time after sunset.
40.) It looks like a sack that encloses with a drawstring.
Answer: Due to the refraction of light it looks like a sack that encloses with a drawstring.
41.) The stars twinkle but we don’t see twinkling of planets.
Answer: Stars twinkles due to the atmospheric refraction of light whereas the planets being nearer to earth does not involves in the atmospheric refraction of light.
42.) The coin in the disappear to have been seen from a specific location. But as soon as the water is poured into the pot to a certain level, the coin appears.
Answer: Due to the refraction phenomenon the coin appears as soon as the water is poured into the pot to a certain level.
43.) A pencil appears to be broken near the surface of water.
Answer: While traveling from one medium to another light changes its direction. Due to this refraction of light pencil appears to be broken near the surface of water.
44.) A convex lens is called a converging lens.
Answer: Convex lens converges parallel ray of light on principal focus. It converges parallel beam of ray on a specific point on the other side of lens. Hence it is also called a converging lens.
45.) Nearsightedness, this defect can be corrected by using spectacles with concave lens.
Answer: The person with the nearsightedness is not able to see the far object clearly. As the distance between eye and lens increases this defect also increases. Concave lens diverges the rays and again this diverged ray can be converged by lens of the eye and hence to cure this defect one can use concave lens of specific focal length.
46.) Farsightedness, this defect can be corrected by using convex lens.
Answer: The person with this defect is not able to see near object clearly. There is an elongation of eye ball the distance between lens and retina decreases. Convex lens converges the ray falling on it. The lens of eye again converges to form the image and hence the convex lens is used to correct defect of farsightedness.
47.) Adults need bifocal lens spectacle.
Answer: After a certain age, some people have problems with myopia as well as hypermetropia. Myopia can be cured by a concave lens of definite power, while hypermetropia is cured by a convex lens and therefore adults need bifocal lenses.
48.) Presbyopia effect is more common in people over 40 years of age.
Answer: Presbyopia is the effect which is seen in old aged people. They find it difficult to see nearby object clearly without spectacles. The focusing power of the of the lens decreases after a certain age and hence it get difficult to see object clearly. And hence presbyopia effect is more common in people over 40 years of age.
49.) Simple microscope is used for watch repairs.
Answer: When the object placed in an simple microscope which has convex lens, the object obtained is erected and larger on the same side of lens than that of object. It is easy to repair the minute hands or second hand of the watch by adjusting the distance between the lens and object. And hence simple microscope is used for watch repairs.
50.) One can sense colours only in bright light.
Answer: The rod shaped cells present in the retina responses only to the intensity of light while cone shaped cells present in the retina responses to many colours. The cone shaped cells present in the retina do not responds to the faint colours and they only responds to the bright colour and hence one can sense colours only in bright light.
51.) The movie cannot be enjoyed if it is too close to the screen in the cinema.
Answer: if we watch the movies very close to our eyes, the more light intensity falls on the eye which results in the contraction of pupil causing strain to the eyes and hence the movie cannot be enjoyed it it is too close to the screen in the cinema.
52.) We cannot clearly see an object kept at a distance less than 25 cm from the eye.
Answer: The clear image of the object is formed on the retina of eye when the eye lens becomes rounded, as it decreases the focal length.
53.) Sodium is always kept in kerosene.
Answer: When sodium comes in contact with the oxygen present in atmosphere or kept in open it causes sudden fire. If we kept sodium in kerosene, sodium does not reacts with it and sink in it. And hence sodium is always kept in kerosene.
54.) Pine oil is use in froth formation.
Answer: In the process of froth formation, ore is mixed with water and pine oil which results in the formation of froth. The contents of minerals present in the concentration of ores are wetted by the pine oil and float on the top layer of the froth. Thus minerals present in the concentration of ore can be separated by pine oil and hence pine oil is use in froth formation.
55.) Lemon or tamarind is use for cleaning copper vessels turned greenish.
Answer: When the copper vessels exposed to air, it reacts with the carbon dioxide present in the air and formation of copper carbonate is occurred on the surface of copper vessel. Lemon contains the citric acid on which reacting with copper carbonate vanishes the greenish layers giving its lustre property.
56.) Anodes need to be replaced from time to time during the electrolysis of alumina.
Answer: In the electrolysis process oxygen get liberated on reacting with the anode to produce carbon dioxide gas. During this process anode get oxidised and hence the anodes need to be replace from time to time during the electrolysis of alumina.
57.) Generally the ionic compounds have high melting points.
Answer: Ionic compounds exist in solid forms. The intermolecular force between the positively charges ions and the negatively charged ions is high and hence the ionic compounds have high melting points.
58.) Adding zinc particles to a solution of copper sulphate makes the blue solution colorless.
Answer: Zinc is more reactive than copper. When the zinc is added to the copper sulphate, the copper get displace form the copper sulphate and the zinc sulphate is formed which is a colourless and hence the blue colour solution get colourless due to the zinc sulphate.
59.) Anodization method is useful for prevention of the corrosion of the aluminium.
Answer: In the process of anodization of aluminium, aluminium is used as anode. The thin layer of aluminium oxide is formed when aluminium is anodised. This layer of aluminium oxide prevents the aluminium from the oxidation and hence prevents from the corrosion of aluminium.
60.) On exposure to air , silver articles turn blackish after some time.
Answer: When the silver is exposed to air, the hydrogen sulphide present in the silver reacts with silver and silver sulphide is formed. It means silver undergoes corrosion which turns silver article blackish after some time when exposed to air.
61.) Magnetic separation method is used to separate the magnetic ingredients in the ores.
Answer: Magnetic separation method needs electromagnetic machine which contains conveyor belt and the iron roller moving continuously. The conveyor belt is an electromagnetic which attracts the magnetic ingredients in the ores and hence the magnetic separation method is used to separate the magnetic ingredients in the ores.
62.) Coins are made from metals and alloys.
Answer: Coin is an alloy made up of metals and alloys because they shows good resistance to the corrosion.
63.) Meena’s mother uses lemon or tamarind for cleaning copper vessels turned greenish.
Answer: When we put copper vessel for long time in open space it gets greenish due to the copper carbonate layer formed on it. The copper carbonate present on the surface of copper vessels when reacting with acid present in lemon, the copper carbonate layer get vanished due to the reaction. Thus, Meena’s mother uses lemon or tamarind for cleaning copper vessels turned greenish.
64.) In the laboratory, sodium is immersed in kerosene.
Answer: Sodium is high reactive metal which reacts with oxygen and other moisture present in air very actively. Hence to avoid the explosive reaction, in laboratory sodium is immersed in kerosene.
65.) Ethylene is an unsaturated hydrocarbon.
Answer: the hydrocarbons having one carbon-carbon double or triple bond are called unsaturated hydrocarbons. If we look into the ethylene( CH2=CH2), the structure of ethylene is found to be double bonded similar to the unsaturated hydrocarbons and hence ethylene is an unsaturated hydrocarbon.
66.) The flame appears yellow in the ignition of naphthalene.
Answer: The flame appears yellow in the ignition of naphthalene because naphthalene is an unsaturated compound and unsaturated compound generally burns with the yellow flame releasing black smoke.
67.) The color of iodine disappears in the reaction between vegetable oil and tincture iodine.
Answer: When vegetable oil reacts with tincture iodine. The vegetable oil with the carbon-carbon multiple bond reacts with tincture iodine and undergoes addition reaction in which unsaturated compound is converted into saturated compound. Hence the color of iodine disappears in the reaction between vegetable oil and tincture iodine.
68.) Vegetable ghee is formed from the hydrogenation of vegetable oil in presence of nickel catalyst.
Answer: Saturated compounds like vegetable ghee are formed due to the hydrogenation of vegetable oil. When the unsaturated carbon molecule chain of vegetable oil is react with hydrogen in the presence of nickel catalyst which converts unsaturated compound into saturated without disturbing the structure and the saturated chains and hence the vegetable oil is formed. Therefore vegetable ghee is formed from the hydrogenation of vegetable oil in presence of nickel catalyst.
69.) Carbon has the property of forming many compounds.
Answer: Carbon forms four covalent bonds with itself and with the elements like oxygen, halogens. It is a tetravalent. It has characteristics called isomerism which in turn results in formation of large number of carbon compounds. Hence carbon has the property of forming many compounds.
70.) Benzene compounds are called aromatic compounds.
Answer: The compound containing alternate double bonds with the ring structured are called aromatic compounds and benzene shows the alternate double bonds with the six membered ring structure. Hence benzene compounds are called aromatic compounds.
71.) The velocity at the earth’s surface must be greater than the escape velocity of the earth.
Answer: To escape the earth’s surface, the spacecraft must have greater velocity at the earth surface. Initial velocity of the space craft must be greater than the escape velocity to escape spacecraft from the earth’s surface.
72.) Space debris can be harmful to the artificial satellites.
Answer: In addition to artificial satellites some other satellites also revolves around the earth. The function of space debris is in such a way that it can collide with other orbits and hence it is said that space debris can be harmful to the artificial satellites.
73.) Satellite launch vehicles are used to place satellites in their specific orbits.
Answer: Satellite launch vehicles are used to place satellites in their specific orbits, because the functioning of this satellite is based on the newton’s third law of motion as it gives equal and opposite reaction on placing.
74.) The Launch vehicles are very costly.
Answer: The launch vehicles are very costly, because we cannot use them repeatedly.
1) Complete the following chart regarding the weight and mass of an object.
Object | On Earth | On Moon |
Mass | X | ………. |
Weight | …… | Y |
Answer:
Object | On Earth | On Moon |
Mass | X | X |
Weight | 6Y | Y |
2) State Newton’s Universal Law of Gravitation.
Answer: According to newton’s universal law every object in the universe attract other object with definite force which is inversely proportion to the Square of distance between two objects and directly proportional to the product of masses of object. The term is known as gravitational force.
3) Define acceleration due to gravity. Write its value on the surface of Earth.
Answer: Accelaration in body under the influence of gravity is called acceleration due to gravity. The value of acceleration due to gravity on the surface of earth is 9.8 m/s2.
4) If a person weighs 750N on Earth, what will be the weight of the person on moon?( The mass of moon is times the mass earth and its radius is times that of 1 81 1 3.7 earth.)
Ans-
5) Mahendra and Virat are sitting at a distance of 1m from each other.Their masses are 75Kg and 80Kg respectively.What is the gravitational force between them? (G = 6.67 x 10 -11 Nm 2/kg 2 )
Answer :-
6) Identify the mistake in the given diagram and draw it again.
Answers –
7) The mass of planet ‘X” is four times that of the earth and its radius is double the radius of the earth. The escape velocity of a body from the earth is 11.2 × 10 3 m/s. Find the escape velocity of a body from the planet ‘X’.
Answer : –
Solution,
Given,
The escape velocity on earth (Vesc) = 11.2 × 103 m/s.
Let Mx be the mass of planet and Me be the mass of earth
Ratio of Mass of X to earth is Mx/Me = 4
Ration of radius of planet to radius of earth is Rx/ Re = 2
The escape velocity is given by formula,
Therefore (Vesc)x = Vesc × 1.414
= 11.2 × 103 × 1.414
= 15.8 × 103 m/s.
The escape velocity is found to be 15.8 × 103 m/s.
8) State the following.
a) Doberenier’s law of Traids:
Answer: Dobereiner introduced elements related to their atomic masses. He introduced term Triad which is a group of three elements having similar chemical properties. These elements were arranged in increasing order of atomic mass and it was found that the atomic mass of middle element is equal to mean of other two elements. But not all elements were classified into Triad.
b) Newlad’s Law of Octaves
Answer: Newland arranged elements in increasing order of their atomic masses of elements. He found that the properties of every eighth element had similar properties that of the first. For example, Potassium has similar properties like Sodium.
c) Mendeleev’s Periodic Law :
Answer: Mendeleev arranged elements in periodic table on the basis of chemical and physical properties of the elements. The vertical columns in Mendeleev’s periodic table is known as Group and horizontal rows are periods.
d) Modern Periodic Law:
Answer: In modern periodic table the elements are arranged on the basis of their atomic numbers. Modern periodic table contains seven horizontal rows and eighteen vertical columns called groups. 118 elements are arranged in modern periodic table. The periodic table is divided into 4 blocks. S-block, p-block, d-block, f-block.
9) Complete the following flow chart.
Answer:
10) In the modern periodic table, the positions of 1 to 20 elements are shown here. Identify the elements A and B. Write their atomic number.
Answer: The element A shown in the diagram is Lithium. The atomic number of element A is 3.
The element B shown in the diagram is Neon. The atomic number of element B is 10.
11) Some elements and their atomic radii are given here.
Arrange them in a decreasing order of their atomic radii. Identify which of the above elements is the biggest atom and which is smallest?
Element | k | Na | Rb | Cs | Li |
Atomic Radius | 2 3 1 | 1 8 6 | 2 4 4 | 2 6 2 | 1 5 1 |
Answer:
1.) Decreasing order of atomic radius is Cs > Rb > K > Na > Li
2.) Lithium is the smallest atom and Cesium is the biggest atom.
12) Complete the following chart.
Shell | N | 2n2 | Electron Holding capacity |
K | 2 × 12 | 2 | |
L | 2 | 8 | |
3 | 2 × 32 | 18 | |
N | 4 | 2 × 42 |
Answer:
Shell | N | 2n2 | Electron Holding capacity |
K | 1 | 2 × 12 | 2 |
L | 2 | 2 × 22 | 8 |
M | 3 | 2 × 32 | 18 |
N | 4 | 2 × 42 | 32 |
13) Find the period in which these elements can be placed.
Answer:
1.) 4Be – The element is placed in period 2. The electronic configuration is 2,2.
2.) 17Cl – The element is placed in period 3.
3.) 2He – The element is placed in period 1.
4.) 13Al – The element is placed in period 3.
14) Electronic configuration of element A is 2,8,1. Answer the following questions based on this information.
a)What is the atomic number of element A?
b)Find the group to which this element belongs.
Answer: a.) The Atomic number of element A is 11.
b.)The above element belongs to the group Alkali metal.
15) Classify the following elements into Metals and Nonmetals. S,Mg,Al,P,N,Na.
Answer: Metals: Magnesium, Aluminium and sodium are the metals.
Non-metals: Sulphur, Phosphorous and Nitrogen are the non-metals.
16) Explain the factors affecting the rate of chemical reaction with example.
Answer: The rate of chemical reaction depends on the nature of reactant. For example, Aluminium reacts highly than zinc. Hence the rate of reaction of zinc is less than the aluminium with the hydrochloric acid.
17) What are reactants and products? Explain with the help of examples.
Answer: The substance present in reaction to the left side when undergoes chemical reaction, those substance are called reactants and the substance which is formed by the chemical reaction is called as product. For example when two molecules of Hydrogen reacts with molecules of oxygen it gives rise to water molecules. here the chemical reaction is given as
2H2 + O2 ——– —> 2H2O
Here, The H2 and O2 are the reactants and 2H2O is the product.
18) Explain the following reaction with their balanced chemical equation .
Answer:
a) Ammonia gas reacts with hydrogen chloride.
Answer: When the ammonia gas reacts with hydrogen chloride to form the salt ammonium chloride in gaseous state. The by product of this reaction is in liquid form. The salt ammonium chloride is in gaseous form get converted into solid form due to the condensation process at room temperature. The chemical equation is as shown below:
NH3 (g)+ HCl (g) ——- –> NH4 + Cl(s)
b) hydrogen sulphide reacts with sulphur dioxide.
Answer:
The reaction of hydrogen sulphide with sulphur dioxide is a redox reaction in which sulphur and water forms as a product.
SO2(g) + 3H2S(g) → 3S(s) + H2O(l)
19) Classify the following reactions into Exothermic and Endothermic reactions.
a) Magnesium ribbon when burned in air, it forms magnesium oxide.
b) HCl + NaOH → NaCl + H2O + Heat
c) 2KClO3(s) → 2KCl(s) + 3O2
d) CaO + H2O → Ca(OH)2 + Heat
e) CaCO3(s) + heat —-> CaO(s) + CO2
Answer: a) Magnesium ribbon on burning in air forms magnesium oxide by releasing heat energy and hence this is an example of exothermic reaction.
b) Hydrogen chloride on reacting with the sodium hydroxide gives Sodium chloride and water on liberating heat and hence the above reacting is an exothermic reaction.
c) Potassium chlorate on heating decomposes slowly and liberates oxygen gas with the product potassium chloride. And hence the chemical reaction occurs on heating so the reaction is endothermic reaction.
d) Calcium oxide on reacting with water gives calcium hydroxide and liberated heat energy and hence the chemical reaction is exothermic reaction.
e) On heating calcium carbonate , it decomposes and liberates carbon dioxide gas with the product calcium oxide. And hence the chemical reaction is endothermic reaction.
20) Distinguish between Direct current and alternating current.
Answer:
Direct Current |
Alternating Current |
Direct current flows in one direction. | Alternate current flows in periodic manner. |
Direct current can be stable, increases or reduces also. It is not oscillatory. | Alternate current is an oscillatory. |
Frequency of DC is zero. | Frequency of AC is 50 Hz |
Magnitude of current does not changes. | Magnitude of current changes. |
21) How does the short circuit form? What is its effect?
Answer: If we switch on the equipment in house, suddenly the electrical fuse wire get melts and electric supply shuts down. This is known as short circuit. To avoid the short circuits we used fuse wire. It is used as a precautionary measure during short circuit.
22)Write Fleming’s Right hand rule and Left hand rule.
Answer: Fleming left hand rule: Fleming’s left hand rule tells us that the direction of the force exerted is perpendicular to the direction of the magnetic field and electric field. In which left hand thumb, index finger and the middle finger are stretched in such a way that the index finger gives the direction of magnetic field, the middle finger gives the direction of current and thumb represents the direction of force on the conductor. This rule is known as Fleming’s left hand rule.
Fleming’s right hand rule: Place your thumb, index finger and the middle finger in such a way that they will be perpendicular to each other, in which middle finger shows the direction of induced current, the thumb shows the direction of motion of the conductor and index finger gives the direction of the magnetic field. This is known as Fleming’s left hand rule.
23) What is an electric motor? In which appliances do we use it?
Answer: Electric motor is a machine that generates mechanical power. And this power is used to rotate fans. It is used in electric cars and electrical appliances.
24) Name any two appliances which works on the phenomenon of magnetic effect of electric current.
Answer: The two appliances which works on the phenomenon of magnetic effect of electric current.
25) Name any two appliances which works on the phenomenon of heating effect of electric current.
Answer: Electric heater and electric cooker are the two appliances which works on the phenomenon of heating effect of electric current.
26) Explain the Right hand thumb rule with the help of diagram.
Answer:
Right hand thumb rule : Fleming’s right hand thumb rule gives direction of magnetic field generated by a current flowing through an electrical conductor. Imagine that you have held in right hand a conductor in such a way that the thumb indicated the direction of current. Now turn your fingers around conductor which gives the direction of the magnetic lines of force. This is known as Fleming’s right hand thumb rule.
27) Explain the importance of fuse wire.(Uses)
Answer: Several times we switch on the electric appliances and suddenly power shut downs as the fuse wire melts and we say that short circuit has been occurred. To avoid the short circuits we used fuse wire. It is used as a precautionary measure during short circuit.
28) Draw a neat and labelled diagram of Hope’s apparatus.
Ans –
29) Name the following diagam appropriately.
Ans –
30) Observe the following diagram and write the answers to the questions given below.
a) Which process does the graph represent?
b) What is the range of temperature responsible for the behaviour?
Answer:
a.) The above graph represents the process of Anomalous behaviour of water.
b.) 0˚C to 4˚C range of temperature responsible for the behaviour.
31) How much heat will be required to raise the temperature of 5kg of water from 20˚C to 100˚C?
Solution:
Given: Specific heat of water c = 1 kcal/kg˚C, Mass of water = 5kg.
According to the principle of heat exchange the energy supplied to water is equal to the energy gained by water i.e. Energy supplied to water = energy gained by water.
Then,
The heat energy (Q) is given by the formula,
Q = mc ∆T
Where,
m is the mass of water molecules,
c is the specific heat of water and
∆T is the change in temperature
Therefore, Q = 5 × 1 × 80
= 400 kcal
Therefore, the heat required to raise the temperature of the 5kg water is 400 kcal.
32) Find the amount of heat needed to raise the temperature of a silver container of mass 100g by 10˚C.(c=0.056cal/g˚C).
Solution,
Given:
mass of silver = 100 g, change in temperature (∆T) = 10 ˚C and specific heat of silver (c) = 0.056 cal/g˚C
According to the principle of heat exchange the energy supplied to water is equal to the energy gained by water i.e. Energy supplied to water = energy gained by water.
The heat energy (Q) is given by the formula,
Q = mc ∆T
Where,
m is the mass of water molecules,
c is the specific heat of water and
∆T is the change in temperature
Therefore, Q = 100 × 0.056 × 10
= 56 cal
Therefore, heat energy required to raise temperature of the silver container is 56 cal.
33) If water of mass 60g and temperature 60˚Cis mixed with water of mass 60g and temperature 40˚C,what will be the maximum temperature of the mixture?
Solution,
Let us consider the maximum temperature of mixture be T˚. Let m1 and m2 be the mass of water which is equal to 60kg. let T1 be the temperature of hot water equal to 60˚C and T2 be the temperature of cold water which is equal to the 40˚C.
According to the principle of heat exchange the heat lost by the hot water is equal to the heat gained by cold water i.e. heat lost by hot water = heat gained by cold water.
Therefore,
Heat lost by water = heat gained by cold water
m1c (T1– T) = m2 c (T2 – T)
We know that m1 = m2 = 60kg
34) Find the amount of needed to raise the temperature of a piece of iron of mass 500gby 20˚C.(c=0.110cal/g.˚C)
Solution,
Given,
Mass of the iron is 500 g
Change in temperature (∆T): 20 ˚C
Specific heat of iron= 0.110cal/g ˚C
Therefore the heat energy (Q) is given as,
Q = m c (∆T)
According to principle of heat exchange,
Energy supplied is equal to the energy gained by the iron piece.
Q = 500 × 0.11. × 20
= 1100 cal
1100 Cal heat is needed to raise the temperature of iron.
35) If the absolute refractive index of water is 1.36,find the speed of light in water.(Speed of light in vacuum=3×10 8 m/s.
Solution,
Given, Absolute refractive index of water is 1.36.
Speed of light in vacuum V1 = 3×10 8 m/s.
Let V2 be the velocity of light in water.
The relation between refractive index and velocity is as follows
n = v1/v2
therefore, V2 = 3×108 / 1.36
V2 = 2.21 ×108 m/sec
The velocity of light in water is found to be 2.21 ×108 m/sec.
36) If the absolute refractive index of glass and water are 3/2 and 4/3 respectively, what is the refractive index of glass with respect to water?
Solution,
Given, The absolute refractive index are the refractive index with respect to vacuum.
The absolute refractive index of glass (n1) = V1/V2 = 3/2
The absolute refractive index of water (n2) = V1/V3 4/3
Let the refractive index of glass with respect to water be 1n2
1n2 = V3/V2
Multiplying and dividing RHS side by V1
1n2 = v1/v2 × V3/V1
= 3/2 × 3/4
= 9/8
Therefore the refractive index of glass with respect to water is 9/8.
37) Solve the following example.
Speed in first medium v1=3×10 8 m/s
Speed in second medium=2×10 8 m/s Then = ? 2 1
Solution,
Given,
Speed of first medium V1 = 3×108 m/s
Speed of second medium V2 = 2×108 m/s
Let the refractive index of second medium with respect to first medium is given as
2n1 = V1/V2
= 3×108 /2×108
= 3/2 = 1.5
Therefore the refractive index of the second medium with respect to the first medium is found to be 1.5.
38) Draw a neat and labelled diagram for: Dispersion of light.
Answer:
39) Observe the given figure and name the following.
Ray AB : | |
Ray NM: | |
Ray MD: | |
Angle R |
Answer:
Ray AB : | Incident ray |
Ray NM: | Refracted Ray |
Ray MD: | Emergent Ray |
Angle R | Angle of refraction |
40) What is refraction of light? Explain with the help of example.
Answer: When the light rays travels from one medium to another medium, the direction of light ray changes. This effect is called refraction of light. For example When light travels from air medium and passes through water medium the light ray changes its path or direction.
41) What is meant by dispersion of light?
Answer: When the light ray passes through any medium, the light get separated into its component colours. This separation of light into its components is called as dispersion of light.
42) State the laws of refraction of light.
Answer: There are two laws of refraction. First law states that the incident ray, normal and refracted ray are on the same plane. According to second law of refraction, the ratio of sin of incidence angle to the sin of refracted angle is constant.
43) If the speed of light in a medium is 1.5×10 8 m/s, what is the absolute refractive index of the medium?
Solution,
Given,
The speed of light in a medium V1 = 1.5 ×108 m/s.
The speed of light in vacuum V2 = 3 ×108 m/s.
Absolute refractive index of a medium (n),
n = 2
Therefore the refractive index of the medium is 2.
44) When a copper coin is dipped in the solution of silver nitrate ,it shows a lusture on its surface. explain this process with the help of chemical equation.
Answer: Silver is less reactive than copper. Copper coin on reacting with the silver nitrate solution, copper displaces from the solution by the removal of white glittering of silver metal. This white glittering of silver is formed on the copper coin.
Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag (s)
45) Electronic configuration of metal A is 2,8,1.Electronic configuration of Metal B is 2,8,8,2.Which of the above metals is more reactive?Explain with reason.
Answer: The metal A shows the electronic configuration 2,8,1 and hence the element is Sodium.
The metal B shows the electronic configuration 2,8,8,2 and hence the element is Calcium.
The metal A is more reactive than Metal B because metal A has 1 electron in its outermost shell and has to lose one electron to make it stable while Metal B has to lose 2 electron as its outermost shell is filled with 2 electrons has to lose 2 electrons to acquire stable electronic configuration
46) Classify the following metals based on their reactivity.
Cu,Zn,Ca,Mg,Fe,Na,Li,Hg
More reactive | Moderately reactive |
Less reactive |
Answer:
More reactive | Moderately reactive | Less reactive |
Ca | Zn | Cu |
Na | Mg | Hg |
Li | Fe |
47) Write the molecular formulas of the following compounds.
a) Cryolite
Answer: The molecular formula of Cryolite is Na3 AlF6.
b) Fluorspar
Answer: The molecular formula of Fluorspar is CaF2.
c) Sodium aluminate
Answer: The molecular formula of Sodium aluminate is NaAlO2.
d) Copper pyrite
Answer: The molecular formula of copper pyrite is CuFeS2.
e) Stanic oxide
Answer: The molecular formula of Stanic oxide is SnO2
f) Ferrous tungstate
Answer: The molecular formula of ferrous tung state is FeWO4
48) Explain the concept of Roasting and Calcination.
Answer: Sulphide ores on heating strongly in the presence of air, converts sulphides into oxides. This process of conversion is called as roasting.
For example zinc sulphide on reacting in the presence of oxygen forms zinc oxide.
Carbonate ores on heating strongly in the presence of limited air, converts carbonates into its oxides. This process of conversion is called as Calcination.
For example zinc carbonate in the presence of limited air on heating gives zinc oxide and liberates carbon dioxide.
49) a)What is an alloy?
Answer: Alloy is an mixture of two or more metals in some proportion to resist the corrosion of metals.
b) Give two examples of alloy.
Answer : – Bronze, brass, stainless steel, and solder etc
50) Explain Bayer’s process.
Answer: In Bayer’s process aluminum ore is heated in the presence of caustic soda product obtained is a water soluble sodium aluminate.
Aluminium ore is called Bauxite. Bauxite has several impurities like Silica SiO2, Ferric Oxide Fe2O3, Titanium Oxide TiO2. These impurities present in bauxite are removed using Bayer’s process.
Bayer’s Process: Solution of sodium aluminate is aluminate in mixed with water and is diluted it is further heated upto 140-150℃ under high pressure for several hours it reacts with aqueous sodium hydroxide.Final product concentrated alumina is obtained by calcination.
Chemical equation for bayer’s process is as mentioned below:
Al2O3.2H2O(s) + 2NaOH (aq) → 2NaAlO2 (aq) + 3H2O (l).
51) Differentiate between Calcination and Roasting.
Answer:
Roasting |
Calcination |
1. In this process ore is heated in the presence of air or oxygen | 1. in calcination process ore is heated in the absence of air or oxygen. |
2. In roasting, sulphides are converted into their oxides | 2. In calcination, carbonates are converted into their oxides. |
3. Sulphide oxides given out in this process. | 3. Carbon dioxide is given out in this process. |
52) Draw a neat and labelled diagram for Froth Floatation Process.
Answer : –
53) Explain the reactions of nonmetals with water with the help of examples.
Answer: Non-metals generally do not react with water except halogens. Halogens reacts with water. for example fluorine on reacting with water gives the hypofluorous acid and hydrofluoric acid in aqueous form.
54) Explain the characteristics of Ionic compounds.
Answer: Ionic compounds are crystalline in nature because of the regular arrangement of ions in compounds. Ionic compounds are soluble in water. Due to the strong attractive force between negatively and positively charged ions, ionic compounds exist in solid state. Melting point and boiling point of ionic compounds are high due to high intermolecular for of attraction.
55) What are amphoteric oxides?Explain with the examples.
Answer: Amphoteric oxides are the oxides that behaves as acidic as well as basic oxides. For example zinc oxide (ZnO) behaves like acidic and basic oxide.
56) Explain the Catenation power.
Answer: The unique property of carbon which shows the ability to form strong covalent bond with other carbon atoms. This strong covalent bond results in the formation of molecules. This unique property of carbon is called as catenation power. The long straight chains, branched chains or ring chains are formed due to this catenation power.
57) Explain the characteristics of covalent bond.
Answer: The covalent bond is a chemical bond formed by the sharing of two electron between two atoms. The covalent bond is represented by a circle or straight line between two atoms. The covalent bond is represented by two structures one is called electron-dot structure and another one is line structure. The covalent bond of carbon to carbon atom is stable because of strong covalent bond.
58) Explain the term Structural isomerism with example.
Answer: The compounds having different structural formula and have the same molecular formula. This phenomenon is called as Structural isomerism. For example butane and iso butane has the same molecular formula but different structural formular.
59)Explain the following terms with example.
a) Oxidising agent
b) Reduction
Answer:
Oxidising agent: Substance which gives oxygen or removes hydrogen is called oxidising agent. Potassium dichromate used as a oxidising agent.
Reduction: The reaction in which substance or reactant loses oxygen and gains hydrogen is called reduction reaction. The substance that is responsible for the reduction reaction is called reducing agent or reductant.
60)Explain the concept of heteroatoms with the help of examples.
Answer: The atom of element which replaces one or more hydrogen atom from hydrocarbon is called as hetero atom. Halogens are the hetero atoms. The group of atoms containing hetero atoms are called as functional group. For example, CH3cl.
61) Explain the following reactions with examples.
a) Addition reaction: When a carbon compound combines with another compound forming new product which contains the atoms of both reactants is called addition reaction. Addition reaction occurs generally in unsaturated compounds because it contains a multiple bond. For example the conversion of methane into methane.
b) Substitution reaction : The reaction in which the position of one atom is replaced one by one by the another atom in presence of sunlight is called substitution reaction. For example, replacing hydrogen atom from methane by chlorine one by one is called chlorination of methane. Here we get four products.
CH4 + Cl2 Sunlight → CH3-cl + HCl
CH3-Cl + Cl2 Sunlight → CH2-Cl2 + HCl
CH2Cl2 + Cl2 Sunlight → CHCl3 + HCl
CHCl3 + Cl2 Sunlight → CCl4 + HCl
c) Esterification: Substances containing esters as a functional group are formed by the reaction of carboxylic acids and alcohols. This reaction is known as esterification. For example, ethanoic acid on reacting with ethanol in presence of ester and acid catalyst gives ethyl ethanoate.
CH3 -COOH + CH3 -CH2 -OH Acid catalyst→CH3 -COO-CH2 -CH3 + H2 O
d) Saponification : Ester on reacting with alkali sodium hydroxide gives alcohol and carboxylic acid. This reaction is known as saponification. It is used in the preparation of soap.
Ester + Sodium Hydroxide → Sodium carboxylate + alcohol
63) What are catalysts ? Give a chemical reaction in which a catalyst is used.
Answer: Catalyst is a substance in the presence of which the rate of chemical reaction changes is called catalyst. The chemical reaction remains unchanged.
For example, potassium Chlorate on heating decomposes slowly.
2KCLO3 ∆→ 2KCL + 3O2
64) Write the characteristics of Ethanol.
Answer: Ethanol is an good solvent. Ethanol is an carbon compound. At room temperature Ethanol is a colourless. The boiling point of ethanol is 78 Degree C. It is soluble in water. It is also called as alcohol. It is found to be in neutral state on testing in aqueous solution.
65)What are vinegar and gasohol? What are their uses?
Answer: Vinegar is the fermented product of ethanol into the ethanoic acid in the presence of bacteria. It is liquid in state. Reaction for the fermentation of ethanol is given below,,
CH3CH2OH + O2 → CH3COOH + H2O.
- Vinegar is used in preservation of pickling.
- Vinegar is used in food preparation.
Gasohol: Gasohol is an fuel. It is an combination of 10% Ethyl alcohol and 90% of Gasoline. It is used as a motor fuel in many countries. It is used in petroleum industries in other countries.
66) Write the uses of ethanol.
Answer: Ethanol is used as a fuel to increase the efficiency of petrol. Ethanol is also used in medicines such as tincture
67)Write the characteristics of ethanoic acid.
Answer:
- Ethanoic acid is a colourless liquid.
- the boiling point of ethanoic acid is 118 degree C.
- The aqueous solution of ethanoic acid is acidic.
- The melting point of ethanoic acid is 17 degree C.
- Because of its freezing nature it is named as glacial acetic acid.
68) What is meant by space debris? Suggest the ways to manage space debris.
Answer: Some other objects are also moving around earth includes non-functioning satellites, parts of launchers separated during launch and Debris created by a collision of a satellite with another satellite or any other object space. By reducing the orbital lifespan of spacecraft space debris can be managed.
69) Bring out the contribution of India’s space missions.
Answer: India has made many contributions in India’s space missions. India has launched various satellites. PSLV and GSLV are the important one. India also contributed to national and social development. India has launched INSAT and GSAT satellites in the field of telecommunication and meteorological field. Internet all over the world is possible due to these satellites. EDUSAT satellite is launched for educational purpose. IRS satellite is for controlling natural resources and disasters. IRNSS satellites are launched to know the exact position on the earth.
70) What is Medium Earth Orbit?
Answer: The satellite orbit having height of orbit in between 2000 Km to 35780 Km is called Medium Earth orbit. These are the geostationary satellites orbit.
71) Calculate the critical velocity of the satellite to be located at 35780Km above the surface of earth.
Answer:
Question 2 b) II. Distinguish between:
1) Universal gravitational constant – Gravitational acceleration of the earth
Answer:
Universal gravitational constant |
Gravitational acceleration of earth |
1. Universal gravitational constant is the force of attraction between two masses at a distance of r from each other. | 1. The acceleration experienced by body under the influence of gravity or the under the condition of free fall due to gravity. |
2. It is denoted by G. | 2.It is denoted by g. |
3. Gravitational constant is scalar in quantity. | 3. Acceleration due to gravity is vector in quantity. |
4. The gravitational constant is never be zero | 4. The value of acceleration due to gravity is zero at the centre of earth only. |
2) Group – Period
Answer:
Group |
Period |
1. The vertical columns in the modern periodic table are known as group. | 1. The horizontal rows in the modern periodic table are known as periods. |
2. There are eighteen vertical columns in the periodic table and hence eighteen groups. | 2. There are 7 horizontal rows in periodic table called periods. |
3. Properties of element in group show similarity and gradation. | 3. Properties of element shows changes while going from one end to another in periods. |
4. Down the group the atomic radius of the element increases. | 4. going from left to right in periodic table, atomic radius decreases. |
3) s-block – p- block
Answer:
S- Block |
P-Block |
1. The s-block contains the group 1 and 2. | 1. The p- block contains the group 13 and 18. |
2. The elements in the s-block are metals. | 2. The elements in p- block are metals, non-metals and metalloids. |
3. The position of s-block elements in the periodic table is at left side. | 3. The position of p-block in the periodic table is at right side in table. |
4. The zig-zag line is not drawn in s- block | 4.The zig-zag line is drawn to separate the metal, non-metals and metelloids. |
4) Group17 – group 18
Answer:
Group 17 |
Group 18 |
1. The elements present in group 17 are halogens. | 1. The elements in group 18 are inert gases |
2. there are seven valence electrons in the outermost shell of element. | 2. In group 18, there are 8 valence electrons. Except helium, it contains 2 electrons. |
3. The valency of element of group 17 is 1. | 3. The valency of elements of group 18 is zero. |
5) Mendeleev’s periodic table – Modern periodic table
Answer:
Mendeleev’s Periodic table |
Modern Periodic table |
1. In Mendeleev’s periodic table, the arrangement of elements are on the basis of the increasing order of their atomic masses. | 1. In the Modern periodic table the arrangement of elements are on the basis of increasing order of their atomic number. |
2. In Mendeleev’s periodic table, there are 8 groups. | 2. In modern periodic table, there are 18 groups. |
3. Isotopes are not placed in exact place. | 3. In modern periodic table isotopes has same place as the element. |
4. Mendeleev’s periodic table is not divided into any blocks. | 4. Modern periodic table is divided into 4 blocks. |
6)Concave lens – Convex lens
Answer:
Concave lens |
Convex lens |
1. It diverges the rays falling on it hence it is diverging lens. | 1. It converge the rays falling on it and hence it is converging lens. |
2. The surface of concave lens is curved in inward direction.
3. it forms virtual image only
|
2. The surface of convex lens is puffed in upward direction.
3. It forms real as well as virtual image. |
4. it forms diminished image | 4. it forms diminished as well as magnified image. |
7)Farsightedness- Nearsightedness
Answer:
Farsightedness |
Nearsightedness |
1. In farsightedness, the human eye could not able to see nearby object clearly. | 1. In nearsightedness, the human eye could not able to see distinct object clearly. |
2. The curvature of cornea and the eye lens decreases in case of farsightedness. | 2. The curvature of cornea and the eyelens increases in case of nearsightedness. |
3. In this case, the object formed is behind the retina. | 3. In this case, the object formed is in front of the retina. |
4. This defect can be cured by using concave lens of suitable focal length. | 4. This defect can be cured by using convex of suitable focal length. |
8)Myopia – Presbyopia
Answer:
Myopia |
Presbyopia |
1. A convex lens is used to correct the defect of myopia. | 1. Concave lens is used to correct the defect of presbyopia. |
2. Human eye unable to see distinct object clearly. | 2. Human eye unable to see nearby object clearly. |
3. The problem of vision is due to the curved lens | 3. This problem of vision is due to the looseness of ciliary muscles. |
9)Metals -Nonmetals (physical characteristics)
Answer:
Metals |
Non-metals |
1. Metals are the good conductors of heat and electricity. | 1. Non metals are the bad conductors of heat and electricity. |
2. it has property of lustre. | 2. non-metals do not have property of lustre. |
3. on reacting metals forms basic oxides. | 3. on reacting non metal forms acidic and neutral oxides. |
4. metals are solid at room temperature. | 4. non-metals are gaseous and solid at room temperature. |
10) Roasting – Calcination
Answer:
Roasting |
Calcination |
1. In this process ore is heated in the presence of air or oxygen | 1. in calcination process ore is heated in the absence of air or oxygen. |
2. In roasting, sulphides are converted into their oxides | 2. In calcination, carbonates are converted into their oxides. |
3. Sulphide oxides given out in this process. | 3. Carbon dioxide is given out in this process. |
11) Froth floatation – Leaching
Answer:
Froth floatation |
Leaching |
1. No chemical reaction is involved in Froth floatation process. | 1. Chemical reaction is involved in leaching process. |
2. froth flotation is based on hydrophilic and hydrophobic property. | 2. Leaching is based on dissolution of ore. |
3. Forth is formed from oil, water. | 3. no froth is formed. |
4. it is used for concentration of copper pyrite. | 4. This process is used for bauxite concentration. |
12)Saturated hydrocarbons – Unsaturated hydrocarbons
Answer:
Saturated hydrocarbons |
Unsaturated hydrocarbons |
1. The Hydrocarbons in which the carbon – carbon atoms are linked to each other with single bond. |
1. The hydrocarbons in which the carbon- carbon are linked to each other with the double and triple bond. |
2. The hydrocarbons are less reactive. | 2. the hydrocarbons are more reactive. |
3. The characteristic property of these hydrocarbons is substitution reaction.
4. The general formula of saturated hydrocarbons is CnH2n+2. |
3. The characteristic property of these hydrocarbons is addition reaction.
4. The general formula is CnH2n. |
13)Open chain hydrocarbons -closed chain hydrocarbons
Answer:
Open chain hydrocarbons |
Closed chain hydrocarbons |
1. It can be straight or branched chain. | 1. It can be ring structure. |
2. In open chain hydrocarbons carbon atoms are linked together by single bond. | 2. carbon atoms are linked together by double or triple bond. |
3. compounds are not aromatic | 3. Compounds are aromatic. |
4. Example: Propane | 4. Example, Benzene |
14)Alkane- Alkene
Answer:
Alkane |
Alkene |
1. Carbon- carbon atoms are linked to each other by a single bond. | 1. carbon- carbon atoms are linked to each other by double bonds. |
2. alkane belongs to saturated hydrocarbons. | 2. alkene belongs to unsaturated hydrocarbons. |
3. The general formula of alkane is CnH2n+2. | 3. The general formula is CnH2n. |
4. The alkanes are less reactive. | 4. The alkenes are more reactive. |
15) High Earth orbit – Medium Earth orbit
Answer:
High Earth orbit |
Medium Earth orbit |
1. The orbit having height greater than or equal to 35780km is called high earth orbit. | 1. The orbit having height restricted in between 2000 km and 35780 km above the earth’s surface is called as medium earth orbit. |
2. It completes one revolution in 24 hours. | 2. It completes 2 revolution in 24 hours. |
3. Geosynchronous satellites revolve in this orbit. | 3. Global positioning satellites revolve in this orbit. |
4 Satellites in this orbit appears stationary | 4. Satellites in this orbit do not appear stationary. |
Que 2B) III.write short notes. (2m each)
1) Escape Velocity : The velocity with planet object escapes the earth’s gravitational field is called escape velocity. It is denoted by Vesc. The escape velocity is given as
Vesc= √(2GM/R)
Where, G = Gravitational constant (6.67 × 10-11 Nm2/kg2)
M = Mass of the planet
R = Radius of planet
2) Free Fall : The motion of an object under the influence of gravity is called free fall. Only gravitational force acts on the object.
3) Anomalous behaviour : The water get contracts instead of expanding when it is heated from 0 degree to 4 degree C. the volume of water becomes minimum at 4 degree C. If we further provide heat to the water, water get expand in between temperature range 0 degree to 4 degree. The volume of water increases and hence the density of water is maximum at 4 degree C. This behaviour of water is called as anomalous behaviour of water.
4) Specific capacity : The property used to measure the amount of heat absorbed by the object is specific heat capacity of that object. It is also defined as the amount of heat necessary to raise the temperature of a object by 1 degree C is called specific heat capacity. The principle of heat of exchange is used to measure the specific heat capacity of a substance by using calorimetry method. It is denoted by C. for water it is 1 cal/g o C.
5) dew point temperature: If the temperature of unsaturated air is decreased in such a way that temperature of unsaturated air is reached at which the air becomes saturated with vapour. This temperature is known as the dew point temperature. Humidity relative to dew point temperature is 100%. It is decided by the amount of vapour present in the air.
6) Regelation : The phenomenon in which ice gets converted into the liquid because of applied pressure and again liquids gets converted into ice by the removal of pressure. This phenomenon is known as regelation.
7) catenation power: The unique property of carbon which shows the ability to form strong covalent bond with other carbon atoms. This strong covalent bond results in the formation of molecules. This unique property of carbon is called as catenation power. The long straight chains, branched chains or ring chains are formed due to this catenation power.
8) characteristics of carbon : The carbon has unique ability which forms strong covalent bond with the other carbon atoms resulting in the formation of large molecules. This unique property of carbon is called catenation power. The carbon compound possess open chain or closed chain of carbon atoms. It can be a ring structured, straight chain structured or branched structure. The covalent bond is stable because of the strong covalent bond between carbon atoms.
9) functional group in carbon compounds: Carbon compounds are formed by the bonding of carbon with other elements like halogen. By replacing hydrogen atoms by the atom of elements satisfies the tetravalency of carbon. The atoms of elements which replace hydrogen atoms in carbon compounds are called hetero carbons. These hetero atoms or the group of atoms containing hetero atoms are called functional groups. For example, CH3 –OH, where OH is the functional group having oxygen as a hetero atom.
10) Homologous series: Homologous series is the series of carbon compounds formed by combining or joining functional group of same property by replacing hydrogen atom following order of increasing length. Depending on the functional groups there are many homologous series. For example, homologous series of aldehydes, homologous series of carboxylic acid, homologous series of alcohols. Again Homologous series of alkanes, alkenes were formed. The members of homologous series are homologous to each other.
11) Aromatic hydrocarbons: Benzene is a cyclic unsaturated hydrocarbon. It has three alternate double bonds in the six membered ring structure. The compounds having this unique characteristics unit in their structure are called aromatic compounds.
12) Moon missions: Moon is the closest astronomical object to earth. The first space mission in solar system called as moon mission. Moon missions have so far been launched by USA, Soviet Union, China, Japan, European countries and India. Luna 2 was the first space craft reached near the moon in 1959. After that, upto 1975, 15 space crafts did analysis of moon and measured the gravity, density and radiations on the moon. Four space crafts were successfully landed on moon and brought stones from the moon for the analysis. In 1969, Neil Armstrong was the first to step on the moon. Later on in 2008, ISRO successfully launched Chandrayaan-1. The important discovery during the mission was the presence of water on the moon. India discovered the presence of water on moon.
Que 2B) IV. Explain the following reactions with the balanced equations.(2 marks each).
1) sodium burns in air
Answer: Sodium on heating, sodium metal combines with oxygen in the presence of air and given sodium oxide.
4Na(s) + O2(g) → 2Na2O(s)
2) reaction of aluminium with oxygen
Answer: Aluminium on reacting with oxygen gives aluminium oxide.
4Al(s) + 3O2(g) → 2Al2O3(s)
3) magnesium reacts with dil hcl
Answer: Magnesium on reaction with dil hydrochloric acid gives salt of magnesium chloride liberating hydrogen gas.
Mg(s) + 2HCL (aq) → MgCl2(aq) + H2(g)= ↑
4) aluminium reacts with dil hydrochloric acid
Answer: Aluminium on reacting with dilute hydrochloric acid gives aqueous aluminium chloride and liberates hydrogen gas.
2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) ↑
5) reaction of Zinc with dil hydrochloric acid
Answer: Zinc on reacting with dilute hydrochloric acid gives Zinc chloride on liberating hydrogen gas.
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2 ↑
6) sulphur burns in air
Answer: Sulphur on heating combines with the oxygen present in air gives Sulphur dioxide.
S + O2 → SO2
7) chlorine dissolved in water
Answer: Chlorine on reacting with H2O gives hypochlorous acid hydrochloric acid.
Cl2(g) + H2O(l) → HOCL(aq) + HCl (aq)
8) sodium aluminate reacts with water
Answer: Sodium aluminate on reacting with the water gives Aluminium hydroxide and sodium hydroxide.
NaAlO2(aq) + 2H2O(l) → NaOH(aq) + Al(OH)3 ↓
9) ferrous dissolved in aqueous solution copper sulphate.
Answer: Ferrous on reacting with aqueous solution of copper sulphate gives ferrous sulphate and copper.
Fe(s) + CuSO4(aq) → FeSOs(aq) + Cu(s)
10)Ferric oxide is reacted with aluminium.
Answer: Ferric oxide on reacting with aluminium gives Iron and aluminium oxide. This reaction liberated heat and hence called as Thermit reaction.
Fe2O3(s) + 2Al(s) ignited→ 2Fe(l) + Al2O3(s) + Heat
11) electrolysis of alumina is done.
Answer: In this reaction Aluminium is formed at the cathode and liberates oxygen at the anode.
Al3+ + 3e– → Al(l) reduction reaction at Cathode
2O2- → O2(g) + 4e– Oxidation reaction at Anode
12) dry aluminium hydroxide is ignited in at1000°c
Answer: Dry aluminium hydroxide on igniting at 1000°c Alumina or aluminium oxide is obtained.
2Al(OH)3(s) heat→ Al2O3(s) + 3H2O(g)
13) zinc sulphide is heated strongly in excess of air
Answer: Zinc sulphide on heating in excess of air gives zinc oxide by liberating sulphur dioxide. This process is called roating.
2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2
14) zinc carbonate is heated strongly in limited supply of air
Answer: Zinc carbonate on heating in limited supply of air gives zinc oxide and liberates carbon dioxide. This process is called calcination.
ZnCO3(s) heat → ZnO(s) + CO2 ↑
15) zinc oxide is treated with carbon
Answer: Zinc oxide on reacting with carbon, zinc oxide reduced to zinc and carbon monoxide.
ZnO(s) + C(s) heat→ Zn(s) + CO ↑
Que 2 B) V. Explain concept with example / explain with the help of balanced equation. (Each 2 m)
1) ionic bond and ionic compounds
Answer: The compound formed by anions and cations are called ionic compounds. Anions and cation are oppositely charges and hence there is electrostatic force of attraction between them. This force is called ionic bond. An ionic compounds are electrically neutral.
For example, Ionic compound HCL is formed by the H+ and Cl– .
2) ganauge
Answer: The unwanted impurities present in the ores are called Gangue. Ores are separated from the minerals economically. The process of separation of Gangue from the ores is called as concentration of ores. Gangue are separated from ores by the process called separation based on gravitation. For example, impurities of Silica separated from Bauxite ore.
3) Ores
Answer: Minerals from which the metals are extracted economically are called ores. Metals can be extracted from their ores by the various methods of separation. For example, Bauxite ore from which aluminium is extracted.
4) Roasting and calcination
Answer: The process of converting sulphides into their oxides in the presence of excess of air is called roasting. For example, Zinc sulphide on heating in excess of air gives zinc oxide by liberating sulphur dioxide.
2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2
The process of converting carbonates into their oxides in the presence of limited air is called as calcination.
For example, zinc carbonate on heating in the presence of limited air gives zinc oxide and carbon dioxide.
ZnCO3(s) heat → ZnO(s) + CO2 ↑
5) corrosion : The process in which the metals get vanished or destroyed slowly by the reaction of air and or other chemicals on the surface of metals. It is known as corrosion. Mostly corrosion occurs with the iron. This iron gets reddish by the action of atmospheric air. Corrosion can be prevented by cutting of the contact of metal with other metals. Corrosion is also prevented by coating a metal with other oil paints or non reactive metals. To prevent the corrosion of any metal grease is applied to the metal surface. The rusting is prevented by this method.
6) Minerals: Answer: The compounds of metal along with their impurities occur in nature are called minerals. For example bauxite is a mineral. The minerals from which their metals are extracted are called ores.
Que.2 B) VI. Draw a neat labelled diagram. ( 2m each.)
1) Magnetic separation method
2) Froth flotation
3) Electrolysis reduction of alumina
4) Hydraulic separation method
5) Electrolysis
6) Anodizing
Que 2 B) VII. Complete flow chart given below ( 2m.each)
1.)
Answer-
2.)
Ans –
3.)
Answer-
For more Questions –