Question

Use the chemical equation to answer the question.

CH
4
​
+2O
2
​
→2H
2
​
O+CO
2
​


This is the chemical equation for the burning of methane gas. Which of the following explains why this process is exothermic?

Answer 1

The reaction is exothermic because the energy released when the product bonds form (the strong C=O bonds in CO2 and O–H bonds in H2O) is greater than the energy required to break the reactant bonds (the C–H bonds in CH4 and O=O bonds in O2). In other words, bond formation releases more energy than bond breaking absorbs, so the net heat is released.