The method we have just looked at, while effective, is tedious and depends on knowing enthalpy changes, etc., for the reactions. It would be more convenient if there were some other more direct way of determining whether a reaction should be spontaneous. Also, there is the temperature problem. And just what exactly does it mean for a process to be "spontaneous"?

Why are some reactions spontaneous at one temperature and non-spontaneous at others? Is there a way to determine what temperatures will make a reaction spontaneous?

We'll see.....