A chemical reaction requires 31.39 kj. how many kilocalories does this correspond to?

Kilojoules (kJ) and kilocalories (kcal) are both units of energy. One calorie is defined as the energy required to increase the temperature of 1 gram of water by 1°C. Also, the conversion factor to be used for this is 1 calorie = 4.184 joules. This is the same as 1 kilocalorie = 4.184 kilojoules. To get the equivalent energy in units of kilocalories, we have the following equation:

31.39 kJ x 1 kcal/4.184 kJ = 7.5024 kcal