Which one to use?

[Lindsey 3C]

There were several formulas that were given to us in lecture, like the ones with constant pressure and delta U, which ones should we use for different situations/ is there a better way to remember them? Do we need to use the integral to solve for some of the ones where delta U= delta H- P(delta V)?

[Richard Colgrove 1A]

I think using ∆U = q+w and then remembering the formula for work (the integral, since it simplifies to the base form -P∆V when pressure is constant) should allow you to derive most of the other equations. Many of the other equations are simply substituting for a term in one of those equations.