Is Hell exothermic (gives off heat) or endothermic (absorbs heat)?
First, we need to know how the mass of Hell is changing in time. So we need to know the rate at which souls are moving into Hell and the rate at which they are leaving. I think that we can safely assume that once a soul gets to Hell, it will not leave. Therefore, no souls are leaving.
As for how many souls are entering Hell, let's look at the different Religions that exist in the world today. Most of these religions state that if you are not a member of their religion, you will go to Hell. Since there is more than one of these religions and since people do not belong to more than one religion, we can project that all souls go to Hell.
With birth and death rates as they are, we can expect the number of souls in Hell to increase exponentially. Now, we look at the rate of change of the volume in Hell because Boyle's Law states that in order for the temperature and pressure in Hell to stay the same, the volume of Hell has to expand proportionately as souls are added.
This gives two possibilities:
If we accept the postulate given to me by Teresa during my Freshman year that, "it will be a cold day in Hell before I go out with you", and take into account the fact that I went out with her last night, then number 2 must be true, and thus I am sure that Hell is exothermic and has already frozen over.
The corollary of this theory is that since Hell has frozen over, it follows that it is not accepting any more souls and is therefore, extinct . . . leaving only Heaven, thereby proving the existence of a divine being which explains why, last night, Teresa kept shouting "Oh my God."