Example 4

In a reaction between graphite and excess dioxygen (oxygen gas)
94.1 kcal heat energy is liberated.
How many kJ of heat energy are liberated? (i.e. convert kcal to kJ)

1 calorie = 4.184 joule
1 kcal = 4.184 kJ

94.1 kcal = 94.1 × (4.184 kJ)
= 393.7 kJ