JSS 3: CARBON AND ITS COMPOUNDS

Carbon is a non-metallic element. The symbol of carbon is C and has atomic number 6. (₆C)

Carbon is found in all living things and forms a large number of compounds known as organic compounds.

Occurrence of Carbon in Nature

Carbon occurs in both free and combined states.

Occurrence of carbon in free state

e.g.

I. Diamond

II. Graphite

III. Coal

Occurrence of carbon in combined state

e.g.

I. Carbon dioxide (CO₂)

II. Methane (CH₄)

III. Calcium carbonate (CaCO₃)

It also occurs in all living organisms as part of organic matter.

                     Allotropes of Carbon 

Allotrope of carbon is the different physical forms in which carbon can exists.

     The ability of carbon to exist in different physical forms is called Allotropy.

The main allotropes of carbon are:

(a) Diamond

(b) Graphite

(c) Amorphous carbon 

                      Diamond

I. It is the hardest natural substance.

II. It is transparent and shiny.

III. It has a crystal structure 

IV. It does not conduct electricity.

Uses of diamond 

I. Diamond is used in cutting glass

II. It is used in drilling rocks

III. It is used in making jewelry.

                        Graphite

I. Graphite is a black, soft, and slippery solid.

II. It has a crystal structure 

II. It is a good conductor of electricity.

Uses of graphite 

I. Graphite is mixed with clay to make the black lead used in pencils.

II. It is used as electrodes in batteries

III. It is used as a dry lubricant for machines and engines.

               Amorphous Carbon

      Amorphous carbon is a form of carbon that does not have a definite or regular shape or crystal structure.

The word “amorphous” means “without form.”

I. It is Black or dark in colour

II. It has no definite shape or crystal structure.

III. It is a poor conductor of electricity.

IV.It can absorb gases and impurities.

V. It can burn in air to form carbon dioxide.

Examples of amorphous carbon include:

I. Charcoal

II. Soot

III. Lampblack

IV. Coke

V. Animal Charcoal (Bone char)

Uses of amorphous carbon 

I. Charcoal

It is used for cooking, heating, and making gunpowder.

II. Coke

It is used as a fuel and in the manufacture of iron and steel.

III. Soot / Carbon black

It is used in making shoe polish, black paints, printer’s ink, and car tyres.

IV. Bone char

It is used in sugar industries to remove colour and impurities.

    

             Destructive Distillation

Destructive distillation is the heating of a substance (such as coal or wood) in the absence or limited supply of air.

It causes the substance to break down chemically and produce several useful products.

Destructive distillation of coal

The products of the destructive distillation of coal are:

Coal → Coke + Coal gas + Coal tar + Ammoniacal liquor

Destructive distillation of wood

The products of the destructive distillation of wood are:

Wood → Charcoal + Wood gas + Wood tar + pyroligneous acid (Wood vinegar)

Uses of Carbon and Its Compounds

1. Charcoal is used for cooking and heating.

2. Graphite is used in making pencils and lubricants.

3. Diamond is used in cutting and drilling tools.

4. Carbon dioxide is used in fire extinguishers and soft drinks.

5. Carbon compounds like petroleum and coal are used as fuels.