Lakhmir Singh and Manjit Kaur Class 8 Science 4th Chapter Materials : Metals And Non-Metals Solution
Lakhmir Singh and Manjit Kaur Science solution: Materials : Metals And Non Metals Chapter 4. Here you get easy solutions of Lakhmir Singh and Manjit Kaur Science solution Chapter 4. Here we give Chapter 4 all solution of class 8. Its help you to complete your homework.
Board – CBSE
Text Book – SCIENCE
Class – 8
Chapter – 4
VERY SHORT ANSWER TYPE QUESTIONS Answers:
(2) Metal : Iron.
Non-Metal : iodine.
(3) (a) – Malleability
(4) Sodium and Potassium are two metals which can soft and can be easily cut with a knife.
(8) Graphite is a non metal which is a good conductor of electricity.
(9) Silicon appears lustrous, but is not malleable nor ductile. It is not good conductor of heat and electricity than the metals. The physical properties of this metalloids tend to be metallic, but their chemical properties tend to be non-metallic.
(10) Metal oxides are compounds composed of metal ions and oxide ions and Non metal oxides are compounds composed of nonmetal atoms and oxygen atoms. This is the main difference between metal oxides and non metal oxides.
(11) Non Metal
(13) Magnesium(Mg) + Oxygen (O2) –> Magnesium oxide (MgO)
(15) Hydrogen is evolved when a metal reacts with water.
(16) Hyrogen gas evolved when a metal react with dilute acid.
(20) The five objects made of metals are:
- Water boilers
- Office furnitures
(21) Iron and aliminium metals are used to make cooking utensils and water boilers for factories.
(22) Copper metal and aluminum metal is used for making electric wires.
(23) Mercury metal is used in making thermometers.
(24) Zinc metal is used for galvanisimg iron to protect it from rusting.
(25) Aluminium foils are used for packaging medicines, chocolate, food items.
(26) Silver and gold metals are used to make jewellery.
(27) The iron present in the blood of our body.
(28) oxygen is the non metal which is essential for maintaining life and inhaled during breathing. (29) Nitrogen is used for making fertilizers.
(30) Chlorine is used in water purification process to make drinking water supplu germ free.
(31) Iodine is a non-metal which is used to make purple-coloured solution which applied on cuts and wounds.
(32) Sulphur and Phosporus is used in fire works
(33) Carbon is used for as a fuel.
(34) (a) False (b) False (c) False (d) True (e) False (f) True (g) False
(35) (a) good; electricity
(f) basic; acidic
(g) acidic; basic
Short Answer Type Questions Answers:
(36) The two physical properties which metals can be distinguished from non-metals :
- Metals are good conductors of heat and electricity. For example : silver, copper , aluminium
Non metals are bad conductors of heat and electricity except diamond & graphite. For example : sulphur & phosphorus.
- Metals are lustrous and can be polished. For example : Gold & silver, Copper
Non metal or non lustrous and cannot be polished except iodine which is a lustrous non metal.
(38) The two properties are:
- If we beat a piece of aluminium sheet with a hammer, we will see that the piece of alumunium metal can be turned into a thin aluminium sheet without breaking
- Also if we heat up a aluminium sheet then that sheet will not burned into ashes.
- Malleability : Metals are malleable, Non metals are not malleable.
- Ductility: Metals are Ductile. Non-metals are not ductile.
- Conductivity: Metals are Good conductors of heat and electricity but Non-metals are not good conductors (excepts in some non-materials)
(40) a> Copper is a good conductor of electricity so copper is used for making electric wires.
b> Graphite is a non-metal which is good conductor of electricity so its used for making electrode in a cell.
c> Metallic substances are good for conduct heat so immersion rods are made of Metallic substances.
(41) a> Malleability : The property which allows the metals to be hammered into thin sheets is called malleability.
b> Ductility : The property which allows the metals to be drawn into wires is called ductility.
(42) a> Malleable : Metals are malleable, it means that metals can be beaten into thin sheets with a hammer.
b> Ductile: Metals are Ductile , it means that metal can be drawn into thin wires.
c> Lustre : Metals are Lustrous, that means metals have a shiny appearance.
d> Sonorousness : Metals are sonorousness, that means metals have rining sounds when we strike them.
(43) Both of two boxes are similar in appearance.
We will do a little experipent to guess the metal box by striking with a small hammer. The box which can produce a ringing sound during striking, will be the one made of metal.
- Copper : Metal.
- Sulphur : Non-metal
- Phosphorus : Non-metal
- Carbon : Non-metal
- Gold : Metal
- Silver : Metal
(45) We cant hold a hot metallic pan which is without a plastic or a wooden handle.
The reason is metal are good conduct of heat so if we hold a hot metallic pan, our skin on hand will burned or will be several injured by heat.
(46) Plastic or wood aren’t good conductor of electricity, so that’s reason screw driver has a plastic or wooden handle.
(47) a> Magnesium oxide : Magnesium hydroxide turns red litumus to blue showing that it is a base. So it is a BASIC
b> Sulphur oxide : sulpher oxide turns blue litmus to red showing that it is an acid. So it is a ACIDIC.
(48) Update Shortly
- Sodium : metal
- Sulphur : non-metal
- Carbon : non-metal
- Magnesium : metal
a> acidic oxides : carbon, sulpher
b> basic oxides : Sodium, Magnesium.
(51) When a copper objects vessel is exposed to moist air for a long time, it will be turned into a green coating called is a mixture of copper hydroxide and copper carbonate.
(52)The material of green coating is a mixture of copper hydroxide and copper carbonate.
If we make a experiment of green coating in water and test it with litmus papers, we will see that turns red litmus paper to blue so it’s a Basic.
(53) a> The gas evolved when sodium reacts with water is Hydrogen.
b> The solution formed by the reaction of sodium with water is Basic.
(54) Depending on their reactivity, some metals reacts violently with dilute acids, some metals react rapidly with dilute acids etc.
Magnesium metal reacts with dilute hydrochloric acid to form magnesium chloride and hydrogen gas. This hydrogen gas burns with a ‘pop’ sound when a lighted matchstick is brought near the mouth of test tube.
(55) When a strip of Zinc metal is placed in copper solution, we would observe that the blue colour of copper sulphate solution faded gradually and red-brown copper metal is deposited on the zinc strip.
Copper sulphate (CuSo4) + Zinc (Zn) –> Zinc sulphate (ZnSo4) + Copper (Cu)
(56) No, Copper metal cannot displace iron from iron sulphate solution.
The reason is a less reactive metal cannot displace a more reactive metal from its salt solution. This replacement reaction does not occur because copper metal is less reactive than iron metal.
(57) (a) Zinc (b) Copper
(58) we can not store Lemon pickle in aluminium utensils because lemon pickle contains acids and this can react with aluminium liberating hydrogen gas. It will be the cause of spoiling the pickle.
(59) The foodstuffs like orange juice, pickels, chutney and curd not be kept in iron or aluminium containers because these all foodstuffs contains acid this can react with aluminium liberating hydrogen gas. It will be the cause of spoiling the pickle.
(60) Sodium and potassium are stored in kerosene because if they kept in open, they can burn and also if they kept in water they can react with water.
If we place a strip of copper metal in zinc sulphate solution then no displacement reaction will take place. This displacement reaction does not take place because copper metal is less reactive than zinc metal.
(61) (a) Metals are sonorous, this means they are capable of producing ringing sounds when we strike them. So metals are used for make bells.
(b) phosphorus kept under the water because it reacts with air and not from water. phosphorus is very reactive non metal and It catches fire if exposed to air. To prevent the contact of phosphorus with oxygen, it is kept under the water.
(62) Any of these materials cannot be beaten into thin sheets because they are non-metals.
|1. Gold||d. Jewellery|
|2. Iron||e. Machinery|
|3.Aliminium||c. Wrapping food|
|4. Carbon||f. Fuel|
|5. Copper||b. Electric wires|
|6. Mercury||a. Thermometers|
(64) One uses of metals given below :
- Iron : Used for make cooking utensils
- Copper : used for making electric wires
- Aluminium : used for packaging medicines, Food items etc.
- Zinc : used for galvanizing iron to protect it from rusting
- Mercury : Used for making thermometers.
(65) One uses of Non-metals are given below :
- Oxygen : Used by plants and animals for breathing.
- Nitrogen : is used for making fertilizers to enhance the growth of plants
- Sulphur : is used for vulcanization of rubber.
- Chlorine : Used for water purification process.
- Iodine : Iodine is used for make purple-coloured solution called ‘tincture iodine’ which is applied on cuts and wounds as an antiseptic.
Long Answer Type Questions Answers:
(66) Metals are malleable and ductile elements which are good conductors of heat and electricity.
Name five metals are :
Non-metals are the elements which are neither malleable, nor ductile.
Name of five non-metals are :
(67) (a) The elements whose properties are intermediate those of metals and non-metals are known as metalloids.
Two metalloids are : silicon, arsenic
- Copper : Metal
- Sulphur : Non-Metal
- Aluminium : Metal
- Oxygen : Non-metal
- Silicon :
- Nitrogen : Non-metal
- Germanium : Metalloids.
- Mercury : Metal.
- Chlorine : Non-metal.
- Sodium : Metal.
(68) (a) When sulphur dioxide dissolves in water then it turns into sulphurous acid and it turns blue litmus to red showing that it is an acid.
Sulphur dioxide (SO2) + Water (H2O) —– > Sulphurous acid (H2SO3)
(b) When an iron nail dissolved into copper sulphate solution, the blue colour of copper sulphate solution fades and a red-brown coating of copper metal is deposits on the iron strip.
Copper sulphate (CuSO4) + Iron (Fe) –à Iron Sulphate (FeSO4) + Copper (Cu)
(69) Five characteristics of metal :
- Metals are malleable and ductile elements which are good conductors of heat and electricity.
- Metals are lustrous or shiny.
- Metals are usually hard and strong.
- Metals have high densities
- Metals are sonorous.
Five characteristics of Non-metal :
- Non-metals are the elements which are neither malleable.
- Non-metals are not ductile
- Non-metals do not conduct heat and electricity
- Non-metals are not lustrous or shiny
- Non-metals have low densities
Five uses of Metals :
- Iron, copper are used to make utensils, and water boilers for factories.
- Copper metal is used for making electric wires for household wiring.
- Aluminium foils are used for packing medicines, chocolate, food items etc.
- Iron metal is used to make nails, screws, nut-bolts etc
- Mercury metal is used for making thermometers.
Five uses of Non-metals:
- Oxygen is a non metal which is used by plants and animalsfor breathing.
- Nitrogen is used in making fertilizers to enhance the growth of plants.
- Chlorine is used for water purification process.
- Sulphur is used for vulcanization of rubber
Iodine is used for make purple-coloured solution called ‘tincture iodine’ which is applied on cuts and wounds as an antiseptic.