Hi all, studying for a physical chemistry exam tomorrow morning and I'm getting really confused. I am hoping somebody has an easy to understand explanation of How alot of this stuff works. specifically the relationships between ΔH, ΔU, q & W and constan P,V & T i.e. if P is constant how these relate VS If T is constant. I understand the derivations of Heat transfer for constant P=constant and V= constant; as well as Wrev and wirr also, I know the ΔU=w+q and dH=dU+d(pv)....is this last one the trick to finding U and H for given process? I guess i dont really have a question, just pumping so much stuff into my head its all spinning around in circles and hoping someone can provide a couple statements that get me back on track. Maybe a good place to start is if you could clearly explain when/where/why Δ_=0 for some of the above, i think maybes that where i getting all mixed up. As always I really appreciate you helpful folks on this forum! Thanks.