Page 69 - Science Class 08

7. Which of the following gas is produced by steam run?
(a) Water gas (b) Coal gas

(c) Producer gas (d) None of these
B. Fill in the blanks.
1. The ________________ the calorific value, the be er is the fuel.

2. Heat liberated in joules on complete burning of one gram of a fuel is expressed as its
________________ value.

3. Charcoal is the example of ________________ fuel.
4. We obtain petrol and other products of petroleum like diesel and kerosene a er
________________ petroleum.
5. The world’s first oil well to obtain petroleum was dug in ___________________ in 1859.
6. Fossil fuels are ________ ,________ and ________ .
7. Process of separa on of different cons tuents from petroleum is called ________ .

8. The least pollu ng fuel for vehicle is ________ .
C. Match the following columns.
Column I Column II

1. Coke a. Hydrogen and carbon monoxide
2. Producer gas b. Toilet goods
3. Water gas c. Good fuel
4. Coal tar d. Nitrogen and carbon monoxide

5. Gasoline e. Unpleasant smell
6. Vaseline f. Petrol gas
D. Write True or False.

1. Petroleum has higher calorific value than that of biogas.
2. Wood has low igni on temperature than that of coal, but coal has high calorific
value than that of wood.
3. Fossil fuels can be made in the laboratory.
4. CNG is more pollu ng fuel than petrol.
5. Coke is almost pure form of carbon.

6. Coal tar is a mixture of various substances.
7. Bituminous coal has high carbon contents than that of anthracite.
8. Coal tar contains about 200 substances which are separated by frac onal dis lla on.

9. People do not like to use natural gas because it is costlier than petrol.
E. Very short answer ques ons.
1. What is fuel?
2. What is calorific value?

3. What is igni on temperature?
4. Name exhaus ble sources of energy.

Science-8 69