Enthalpy

What is Enthalpy? 

The following video does go further than you need, but gives a good explanation:

Enthalpy: Understanding why enthalpy can be viewed as "heat content" in a constant pressure system.

Enthalpy of Formation

Heat of Formation: Standard heat of formation or standard enthalpy change of formation.

Enthalpy of Formation values can be very useful for calculating the enthalpy change in a reaction. There are two ways to do this:

METHOD ONE

• Find the sum of the enthalpies of formation of the products.
• Find the sum of the enthalpies of formation of the reactants.
• Subtract the latter from the former.

METHOD TWO

• Write out the equations that each enthalpy of formation represents
• Use Hess' Law

Hess's Law and Reaction Enthalpy Change: Using Hess's Law and standard heats of formation to determine the enthalpy change for reactions