Most chemicals will decompose if heated strongly enough, requiring energy to break chemical bonds in an endothermic process. Bond-breaking being endothermic means that bond-making is exothermic, releasing energy when chemical bonds are formed.

1. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
1 of 35 © Boardworks Ltd 2007

2. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
2 of 35 © Boardworks Ltd 2007

3. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
energy
absorbed
3 of 35 © Boardworks Ltd 2007

4. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
energy
absorbed
4 of 35 © Boardworks Ltd 2007

5. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
energy
absorbed
Because bond-breaking is endothermic, bond-making must
therefore be exothermic. This means that energy is
released when chemical bonds are made.
5 of 35 © Boardworks Ltd 2007

6. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
energy
absorbed
Because bond-breaking is endothermic, bond-making must
therefore be exothermic. This means that energy is
released when chemical bonds are made.
6 of 35 © Boardworks Ltd 2007

7. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
energy
absorbed
Because bond-breaking is endothermic, bond-making must
therefore be exothermic. This means that energy is
released when chemical bonds are made.
energy
released
7 of 35 © Boardworks Ltd 2007

8. Making and breaking chemical bonds
Most chemicals will break up (decompose) if they are
heated strongly enough. This means that energy is needed
to break chemical bonds – an endothermic process.
energy
absorbed
Because bond-breaking is endothermic, bond-making must
therefore be exothermic. This means that energy is
released when chemical bonds are made.
energy
released
8 of 35 © Boardworks Ltd 2007