Fuels, Combustion and Flame Worksheet-4

Fuels, Combustion and Flame Worksheet-4

1. L.P.G used as domestic fuel is mixed with a strong smelling volatile liquid known as Ethyl Mercaptan for:

(a) better combustion                 (b) good smell/fragrance

(c) detection of gas leakage        (d) higher calorific value

2. Which of the following has the characteristics of a good fuel?

(a) Coke             (b) Butane         (c) Coal              (d) Kerosene

3. Respiration is also a slow combustion reaction. During respiration, oxygen gas is inhaled which combines with hemoglobin of blood to form oxyhemoglobin which digest the food.

Which of the following distinguishes respiration from combustion?

(a) Requirement of oxygen

(b) Exothermic nature of reactions

(c) Energy can be released only in the form of heat only

(d) Can take place at any temperature

4. When water is poured over burning wood, the fire goes off. This is because:

(a) temperature of wood decreases

(b) temperature of water goes up

(c) molecules of water reacts with oxygen present in the flame

(d) the flame vapourises

5. Which of the following is an example of rapid combustion?

(a) burning of wood                     (b) burning of LPG

(c) burning of cracker                 (d) burning of a candle

6. The blue zone in a LPG flame indicates:

(a) unburnt vapours

(b) partial decomposition

(c) moderately hot

(d) hottest and complete combustion

7. Which of the following fuels has the highest calorific value?

(a) Petrol           (b) Coke             (c) Natural gas (d) Kerosene

8. LPG is mainly a mixture of two hydrocarbons:

(a) butane + ethane                     (b) butane + isobutane

(c) propane + ethane                   (d) methane + ethane

9. The heat produced by burning 1 g of fuel completely is known as:

(a) heat capacity                           (b) calorific value

(c) vapour density                        (d) boiling point

10. which among the following is the best fuel?

(a) Wood 4000 Cal/g                  (b) Coke 8000 Cal/g

(c) Coal 7000 Cal/g                     (d) Kerosene 11,200 Cal/g

Answer Key:

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