Units of Energy

Units of Heat Energy:

 Heat is expressed in units of Joules (J), which is the SI unit of energy. The symbol for heat in our equations will be “q.”

 1000 Joules (J) = 1 kilojoule (kJ)

•  Reactions which LOSE heat are called exothermic reactions. They may have negative heat values.
• Reactions which GAIN heat are called endothermic reactions. They may have positive heat values.

The non-SI but common unit for energy is the calorie or kilocalorie (kcal). We can convert between the two.

 1 kcal = 4.184 kJ