Pressure question
 

In a mixture of 10.0 g each of H2, O2, Ar, and Kr, which gas exerts the greatest partial pressure?

As I explained before in another topic partial pressure depends on how many mole of the substance is present in a mixture.

So we got 10 grams of each. How many mole are the oxigen hidrogen kripton argon, which one is more?

10 g of H2 = 5 mol of H2
10 g of O2 = 0.3125 mol O2
10 g of Kr = 0.1193 mol Kr
10 g of Ar = 0.2105 mol Ar

Hidrogen is the winner. Pi = P*(ni/n) so which gas has more mols in the mixture has more partial pressure.