- Exothermic reaction: a chemical reaction that produces heat.
- ∆H = negative
- Reactants contain more energy than the products. E1 > E2
- Chemical energy decreases during the reaction and is converted to heat energy (heat is given out).
- Total heat energy given out during the formation of chemical bonds > Total heat energy absorbed during the breaking of chemical bonds.
- Temperature of the surroundings increases i.e. the reacting mixture becomes hot.