What weight of H2 at STP could be contained in a vessel that holds 4g of oxygen at STP?

Question

First, I used the Ideal Gas Law to find the volume of oxygen at STP, but im not sure what to do from there..

Answer 1

Use PV = nRT again. You know volume from the previous work, then plug in R, T, and P, calculate n for H2. Then moles = grams/molar mass will allow you to calculate grams.