Complete the crossword Fig. 5.2 with the help of the clues:

Across

1. Fuels obtained from dead remains of living organisms. (6,5)

2. A process by which the various constituents of petroleum are separated. (8)

3. A porous black substance obtained from coal. (4)

4. Another name for motor fuel. (6)

Down

5. The substance obtained by carbonization. (4)

6. Fuel for heavy motor vehicles. (6)

7. A petroleum product used for road surfacing. (7)

8. Dead remains of sea animals got converted into it. (9)

1) Fossil fuels

Fossil fuels are obtained from dead remains of living organisms i.e. plants or animals. Examples are coal, petroleum, natural gas etc.

2) Refining

The various constituents of petroleum are separated by refining process in a refinery. This method employs fractional distillation technique. Petrol, diesel, kerosene, paraffin wax, LPG etc. are obtained by this process.

3) Coke

Coke is a product obtained by destructive distillation of coal. It is a tough, porous and black solid substance used as a fuel.

4) Petrol

Petrol is commonly used as a fuel in vehicles which is known as motor fuel.

5) Coal

Coal is obtained by slow decomposition of dead remains of plants under earth’s surface in absence of air under high pressure and temperature. This process is called carbonization.

6) Diesel

Diesel is used as a fuel for heavy motor vehicles. It is one of the product obtained from refining of petroleum.

7) Bitumen

Bitumen is obtained by refining of petroleum which is used for metalling the roads.

8) Petroleum

Petroleum is obtained from dead remains of sea animals which settled down in the bottom of sea and get covered with sand, mud, clay. Due to high pressure, temperature and in absence of air they slowly gets converted into petroleum.