Hess' Law

Hess’ Law

• States the overall standard enthalpy change of a reaction is same regardless of whether the reactions takes place in one step or several steps

• This allows you to break a reaction into steps and the enthalpy changes to find total enthalpy change for an overall reactions

Example

• Calculate enthalpy change for the reaction - 2C + 2H + O₂ → CH3COOH

∆H =