IB Chemistry R1.4 Notes

In Topic R1, you learned more about enthalpy changes and in general, you have learned about how exothermic and endothermic reactions change the stability of chemical compounds. The next component you need to know is how this stability reflects the likelihood of a reaction occurring, termed spontaneity.

A spontaneous reaction is a reaction that occurs without energy input. However, both exothermic and endothermic reactions can be spontaneous even though endothermic reactions typically require an energy input. This is because spontaneity depends on three factors:

1. Enthalpy
2. Temperature
3. Entropy