Yeah GCSEs aren't that hard. Most of my friends and I left the revision until study leave and even then...I revised for 3 subjects: Physics, History and Electronics. Wtf was I doing taking Electronics? I cry myself to sleep every night pondering.
And that moles shit...all you really need to know is moles=mass/volume. 1 mole has about 6.023 x 10^23 particles of any one element. But the thing you were talking about was probably...
1 mole of any gas occupies 22.4dm^3. Not sure if that's room temperature or what the pressure is but since I have to learn it, I should really look it up.
Yeah, I should really get back to revising as well. My first exam is Wednesday. I've always wanted to tutor someone cos I reckon I'd be good at it.