Entropy and Gibbs Energy?

How you calculate each of these depends on the information you have available to you. Most chemistry texts have a table of standard entropy values for a lot of different compounds. The change in entropy is calculated as:

Delta S = Standard entropy of products - standard entropy of reactants

In those same tables, you can often find standard free energy of formation, and the change in free energy can be calculated in basically the same manner. You can also calculate the free energy change using

Delta G = Delta H - T Delta S where Delta H is the change in the enthalpy of the reaction.

The sign of Delta G for a reaction tells you whether the reaction is spontaneous or not, meaning whether the reaction releases energy in a form which can do work or not.