Selina Concise Class 8 Chemistry Chapter 9 Carbon and it’s Compound Solution

Selina Concise Class 8 Chemistry Solution Chapter No. 9- ‘Carbon and it’s Compound’ For ICSE Board Students.

1) a) .…………..is present in both living and non living things.

Answer :  Carbon

Explanation: Carbon is present in both living and non living things carbon present in some living things ( Humans , plants, insect, etc) called organic carbon , and carbon present in non living things ( rock, pen, building etc ) are called inorganic carbon.)

b) The tendency of an element to exist in two or more forms but in the same physical state is called ………………

Answer : Allotropy

Explanation: The elements have different form , properties , but same physical state known as Allotropy.

c) ………….. and ………….. are the two major crystalline allotropes of carbon.

Answer : Crystalline and Non crystalline

 Explanation: Crystalline allotropes are the homogeneous mixture of atom or elements in which particles are arranged in definite order, and non crystalline allotropes of carbon are the irregular arrangements of particles , which is Heterogeneous mixture .

d) ………….. is the hardest substance that occur naturally.

Answer : Diamond

Explanation: Diamond is the hardest substance,  outermost four electrons of carbon atom shared electrons with  four electrons of carbon atoms and make  very strong bond (extremely rigid tetrahedral crystal ) so due to this strong arrangements of molecules diamond become hardest substance.

e) The name carbon is derived from a Latin word …………….

Answer : Carbo

Explanation: Carbon is derived from Latin word carbo , the meaning of carbo is coal.

2) a)

Answer :  iv) Petroleum :

(Combined state of carbonoccur as petroleum which is consistent of hydrocarbons )

b) 

Answer : iii) Sugar

(The crystalline form of carbon is a sugar , in which carbon atoms are covalently bonded to each other)

c)

Answer : ii) Maharashtra

(Graphite is not found in Maharashtra )

d)

Answer : iii) cutting and drilling rocks and glass

( Diamond is used for cutting and drilling rocks and glass)

e)

Answer : Carbon atoms can form long chain

(Carbon forms innumerable compounds because carbon atoms can form long chain)

3) a)

Answer :   True

b)

Answer :  False

c)

Answer :  False

d)

Answer :  True

e)

Answer : True .

4)

a)

Answer :  Allotropy:

The elements have different form , properties , but same physical state known as Allotropy.

b)

Answer : Carat :

A unit of weight for measuring Precious things like , diamond gold etc .

c)

Answer : Crystal :

Homogeneous solid mixture in which atoms or molecules are placed in definite order and this solid have definite geometrical shaped know as crystal .

d)

Answer : Catenation :

The bonding of identical atoms to form long chain, like branches structure , cyclic structure are known as catenation.

5) a)

Answer: Crystal :- Crystal is a substance whose atom or molecules are arranged in a definite pattern.

b)

Answer: Allotropy:-Allotropy is a different form of an element  found in the same physical state.

c)

Answer: Catenation :-The property by which atom of an element link together to form long chain or ring compound .

6) a)

Answer :  Diamond

b)

Answer :  Graphite

c)

Answer : Fullerenes

7) a)

Answer : Graphite is a good conductor of electricity but not diamond  because  graphite have delocalised or free electrons that’s why graphite is good conductor of electricitybut indiamond not having free electrons , all four electrons present outermost orbit of carbon atom used for making covalent bond that’s  why  diamond is bad conductor of electricity.

b)

Answer : diamond is very hard because outermost four electrons of carbon atom shared electrons with  four electrons of carbon atoms and make   very strong bond (extremely rigid tetrahedral crystal ) so due to this strong arrangements of molecules diamond become hardest substance.

c)

Answer : Fullerenes consists of carbon atom which is connected to each other with single and double bond to form spherical cage like structure or Bucky balls shape . Most common Fullerenes are Buckminster or Bucky- ball.

d)

Answer : Copper oxide as a impurity present in black diamond.

8) a)

Answer : Graphite :

  • Graphite used for making electronic products like electrodes , batteries , solar panel.
  • Graphite is used form making pencil lead.
  • Graphite used for making lubricant.
  • It is used for making black paint and ink.

b)

Answer : Diamond :

  • Diamond is lustrous property due to this diamond used for Jewellery as a gem.
  • Diamond is hardest substance due to this diamond is used for cutting or drilling of rocks and glass .
  • Diamond also used for industrial purpose.

9).

Answer :

Sr.No. Graphite Diamond
1 Graphite is a black and opaque substance Pure diamond is transparent.
2 Graphite is soft and slippery to touch. Diamond is hardest substance.
3 Graphite is good conductor of electricity. Diamond is poor conductor of electricity.
4 Density of graphite is less than diamond. Density of diamond is more than graphite.
5 It occurs as octahedral crystals. It occurs as hexagonal crystals.
Updated: July 13, 2021 — 11:17 pm

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