Fuels, Combustion and Flame Worksheet-8

Fuels, Combustion and Flame Worksheet-8

1. Arrange the following fuels in increasing order of their calorific value:

1 – Petrol

2 – Diesel

3 – Kerosene

4 – Natural gas

(a) 1, 2, 3, 4       (b) 2, 3, 4, 1       (c) 2, 1, 3, 4       (d) 2, 3, 1, 4

2. Incomplete combustion of a fuel gives:

(a) CO                (b) CO₂               (c) SO₂               (d) oxides of nitrogen

3. Total amount of heat produced by a fuel having calorific value of 20 kJ /kg was found to be 50,000 Joules. How much fuel was burnt?

(a) 2500 kg       (b) 250 kg          (c) 25 kg             (d) 2.5 kg

4. Combustion is an:

(a) exothermic reaction              (b) endothermic reaction

(c) displacement reaction          (d) reduction reaction

5. In spite of danger involved with hydrogen, it is used as fuel for some applications. What are these?

(a) Rocket fuel                              (b) Oxyhydrogen flame

(c) Car fuel                                     (d) all of these

6. A family consumes 12 kg of LPG in 30 days. Calculate the average energy consumed per day if the calorific value of LPG is 50kJ/kg.

(a) 10,000 J/day                          (b) 15,000 J/day

(c) 20,000 J/day                          (d) 25,000 J/day

7. Inflammable substances have an ignition temperature:

(a) more than 100°C                   (b) less than 100°C

(c) more than 200°C                   (d) between 200°C to 350°C

8. The disadvantages of incomplete combustion is/are:

(a) unburnt carbon gets released

(b) air is polluted

(c) may cause respiratory problems

(d) all of these

9. Type of flame produced by a fuel depends upon:

(a) calorific value

(b) amount of oxygen

(c) type of fuel and its chemical composition

(d) all of these

10. Which of the following statements is NOT true?

(a) CO₂ is the best fire extinguisher

(b) Global warming can cause acid rain

(c) Burning of coal and diesel releases sulphur dioxide gas

(d) LPG has higher calorific value than biogas

Answer Key:

(1)-(b); (2)-(a); (3)-(d); (4)-(a); (5)-(d); (6)-(c); (7)-(b); (8)-(d); (9)-(b); (10)-(b)