Question

"The calorific value of cooking gas (LPG) is 50 kJ/g". What does it mean? 

Answer 1

When you say that the caloric value of cooking gas (liquefied petroleum gas, or LPG) is 50 kJ/g, it means that when 1 gram of LPG is burnt completely, it produces 50 kilojoules of energy in the form of heat.