How can one determine the enthalpy change of a reaction, specifically, how to find delta H of a reaction?

To determine the enthalpy change of a reaction, you can use Hess's Law or measure it experimentally using calorimetry. Hess's Law involves adding or subtracting the enthalpies of known reactions to find the overall enthalpy change. Calorimetry involves measuring the heat released or absorbed during a reaction to calculate the enthalpy change.