Question

Fuel	Calorific Value (kj/g)
charcoal	33
coal	25.33
wood	17
diesel	45
kerosene	48
petrol	50
biogas	35 to 40
butane (LPG)	50
methane	55
hydrogen	150

Based on the table above, which of the following is the correct sequence in which the fuels that give out most heat to the least heat energy will be arranged?
(a) hydrogen, wood, coal, biogas, methane
(b) methane, kerosene, diesel, charcoal
(c) coal, kerosene, petrol, hydrogen
(d) hydrogen, butane, diesel, kerosene

Answer 1

(b) methane, kerosene, diesel, charcoal

Calorific value is nothing but the amount of heat energy evolved when 1 g of a fuel is burnt completely in the presence of oxygen. Based on the calorific value, methane gives the highest heat energy with 55 kJ/g, which is followed by kerosene with 48 kJ/g and diesel with 45 kJ /g. Charcoal gives the least amount of heat energy, i.e. 33 kJ/g.