So reacting chemicals have more than just reactants becoming products, there is also changes in the heat of a compound, with it either being absorbed or released, as it is necessary for breaking bonds. The two types of reactions, Exo and Endo are gone over
HERE, as it is sort of hard to tell which is which sometimes, but this image should help:
Heat movement is really the transfer of energy, and as such there are two types of energy, Kinetic and Potential. Kinetic energy is the energy of motion, KE = 1/2mv^2. Potential is the energy stored. The difference is showed by the image here:
And
HERE is a video on it, with a quiz.
The last thing you need to know is MCAT.
is actually a an equation that looks a little like:
And
HERE someone goes over how to do it for you.
And that is all