Question

How do partial pressures affect each other?

Answer 1

I'm assuming you're referring to specifically ideal gases. Partial pressure is just the fraction of the total pressure a gas happens to take up in a container. If the partial pressure of `H_2(g)` is 0.2 atm, then it takes up 20% or so of a container with 0.2 atm `H_2(g)` and 0.8 atm of other gases like `N_2(g)` and `Ar(g)`.

One relevant virtue of ideal gases is that they do not interact whatsoever. They elastically collide with each other and do not "stick" to their containers. So, partial pressures are like percents of total pressure for ideal gases.