Question

What determines the amount of chemical energy a substance has?

Answer 1

Chemical energy  is the kind of energy stored in the bonds formed by atoms and molecules in chemical compounds and elements.  This energy is  released during a chemical  reaction and  heat is often given out in the process. These kind of reactions where heat is given out as a by product are called exothermic reactions.

The major factor that determines how much chemical energy a substance has is the mass of that substance. Mass is defined as the amount of matter in a substance.

The higher  the mass of a substance, the more concentrated that substance is and subsequently the greater the number of atoms and molecules.

Logically, the higher the number of atoms and molecules  then the greater the number of bonds in that substance and subsequently the more the amount of chemical energy  stored therein.