That's not the bit I find difficult, i'm so stupid i can't explain. I'm revising that stuff tomorrow evening, would you mind going through a question tomorrow? Then I can show you what bit I don't get.<quoted text>
Well, PV=nRT is fairly straightforward. Think of it in stages. Suppose you have a given amount of gas and you compress it. What will happen? The pressure will go up. How about if you heat it? The pressure will go up. how about if you put more in? The pressure will go up. The point is that there is one constant, R, that works well for all gases. So, if you know P,V, and T, you can figure out how much of the gas there is (n). Or, correspondingly, if you now how much there is and what the temperature and pressure is (n,P,T), you can determine the volume.
As for q=mc*(delta T), remember that c is the amount of heat required to raise one mole (or gram, depending on your specific definition--be careful) by a temperature of 1 degree. So, if you raise it by 2 degrees, it takes twice as much heat. If you have twice as much of the material, it takes twice as much heat to raise it all by that 1 degree.
My lecturer is so annoying, he doesn't know how to explain things. I end up getting more confused.