This power point introduces enthalpy and has several examples on solving different heats of reaction problems.
This is an example problem of solving the heat of a reaction using Hess' law. It shows step by step what to do with each piece of information given. Don't skip this!!!
Every chemical reaction involves the breaking and formation of chemical bonds. Because of this, energy is an important aspect of these processes. This reading defines and describes enthalpy - the energy of chemical reactions.
Here is an example of using [products - reactants] to find the heat of a reaction. Since enthalpy, entropy and free energy are all state functions, you can use this method to calculate these quantities for any reaction given the standard values.
A basic video defining and contrasting exothermic and endothermic changes.
Source: chemistNATE youtube channel