Describe the change in energy that occurs as bonds are broken and formed

When bonds are formed energy is released.

When bonds are broken energy is required or absorbed.

Explanation:

The energy changes occur during the bonds formation and bonds breaking.

There ere two types of reaction endothermic and exothermic reaction.

Endothermic reactions:

In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O → CO + H₂

ΔH = + 131 kj/mol

it can be written as,

C + H₂O + 131 kj/mol → CO + H₂

Exothermic reaction:

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

Chemical equation:

C + O₂ → CO₂

ΔH = - 393 Kj/mol

it can be written as,

C + O₂ → CO₂ + 393 Kj/mol