Which of the following reactions shows that the formation of CO2 releases 393.5 kJ/mol?
A. C(s) + O2(g) → CO2(g) + 393.5 kJ
O B. C(s) + 20(g) + 393.5 kJ → CO2(9)
O C. C(s) + O(g) + CO2(g) + 393.5 kJ
D. C(s) + O2(g) + 393.5 kJ → CO2(g)

A. C(s) + O2(g) → CO2(g) + 393.5 kJ

Explanation:

The formation of carbon IV oxide (CO2) is an exothermic process. n exothermic process is a chemical process in which heat is evolved. Speaking in lay man's terminology, heat is one of the 'products' of the reaction. This implies that heat is evolved by the process.

The formation of CO2 is always a combustion reaction where heat is evolved or released by the reaction system. Hence the reaction could be shown as;

C(s) + O2(g) → CO2(g) + 393.5 kJ

This implies that 393.5 kJ of energy is released in the reaction in the form of heat. Hence the answer given in the answer box.