Carbon and its Compunds

Question 1

What is carbon known to people for?

Answer 1

Charcoal, soot, and diamond

Carbon occurs in pure forms as diamond, graphite, and fullerene, and in impure forms like coal and petroleum.

Question 2

What is catenation?

Answer 2

The ability of carbon to form bonds with other carbon atoms to create carbon frameworks

This property allows for the formation of complex organic molecules.

Question 3

Define allotropy.

Answer 3

The existence of two or more structural forms of the same element in the same physical state.

Question 4

What are allotropes?

Answer 4

Different forms of the same element in the same physical state.

Question 5

Name one element that exhibits allotropy.

Answer 5

Carbon

Other elements include sulphur and phosphorus.

Question 6

What are the two types of allotropes of carbon?

Answer 6

Crystalline forms and amorphous forms.

Question 7

What are the crystalline forms of carbon?

Answer 7

Diamond, graphite, and fullerene.

Question 8

What is diamond?

Answer 8

The purest form of naturally occurring carbon, found as colorless, lustreless solids.

Question 9

Describe the properties of diamond.

Answer 9

• Hardest known substance
• High melting point
• Dense and resistant to high temperatures
• Non-conductor of heat and electricity

Question 10

List two uses of diamond.

Answer 10

• Industrial drills for mining
• Jewellery due to its high refractive index

Question 11

What is graphite?

Answer 11

A form of carbon that exists as black, slippery, hexagonal crystals.

Question 12

Describe the properties of graphite.

Answer 12

• Opaque, soft crystalline solid
• Metallic lustre
• Chemically inert
• Good conductor of heat and electricity

Question 13

List two uses of graphite.

Answer 13

• Lubricant in engines
• Electrodes in electroplating

Question 14

Who discovered fullerenes?

Answer 14

H. W Kroto, E. Smalley, and R. F Curl.

Question 15

How are fullerenes made?

Answer 15

By heating graphite in an electric arc in the presence of inert gas like Helium or Argon.

Question 16

What is coal?

Answer 16

A principal source of fuel and energy, formed from buried remains of forests under pressure and temperature.

Question 17

Name the four main types of coal based on carbon content.

Answer 17

• Peat (20-30% carbon)
• Lignite (40% carbon)
• Bituminous (60-70% carbon)
• Anthracite (90% carbon)

Question 18

What is destructive distillation of coal?

Answer 18

Heating coal to high temperatures in the absence of air, leading to decomposition.

Question 19

What products are formed from the destructive distillation of coal?

Answer 19

• Coal gas
• Coal tar
• Ammoniacal liquor
• Coke

Question 20

What is activated charcoal?

Answer 20

Charcoal treated with steam to increase its ability to absorb gases.

Question 21

What is lamp black (soot)?

Answer 21

A deposit obtained by burning the wick of an oil lamp excessively.

Question 22

What is producer gas?

Answer 22

A mixture of carbon (II) oxide and nitrogen, prepared by passing air through red-hot coke.

Question 23

What is water gas?

Answer 23

A mixture containing carbon (II) oxide and hydrogen, prepared by passing steam over hot coke.

Question 24

What percentage of air is carbon (IV) oxide (CO2)?

Answer 24

0.03% by volume.

Question 25

How is carbon (IV) oxide prepared in the laboratory?

Answer 25

By the action of dilute HCl or HNO3 on a trioxocarbonate (IV).

Question 26

What are the physical properties of carbon (IV) oxide?

Answer 26

* Colourless and odourless gas * Denser than air * Soluble in water * Weak acidic gas

Question 27

What happens when carbon (IV) oxide reacts with water?

Answer 27

It forms trioxocarbonate (IV) acid.

Question 28

What is carbon (II) oxide (CO)?

Answer 28

A poisonous, colourless, and odourless gas produced by incomplete combustion of carbon compounds.

Question 29

What is the laboratory preparation method of carbon (II) oxide?

Answer 29

By the action of concentrated H2SO4 on methanoic acid.

Question 30

What is the main use of carbon (II) oxide?

Answer 30

As a reducing agent in the extraction of metals.

Question 31

What are trioxocarbonates (IV)?

Answer 31

Salts derived from trioxocarbonate (IV) acid when it reacts with metals or other salts.

Question 32

What is the carbon cycle?

Answer 32

The continuous circulation of carbon in nature through various processes.

Question 33

List processes that release carbon (IV) oxide into the atmosphere.

Answer 33

* Respiration of living organisms * Burning of carbon-containing substances * Decay of organic materials * Fermentation of sugars * Heating of trioxocarbonates

Question 34

List processes that remove carbon (IV) oxide from the atmosphere.

Answer 34

* Photosynthesis * Dissolution in rainwater and natural water bodies