At STP conditions, 0.25 mole of CO 2 (g), H 2 (g), NH 3 (g) will:

1 mole of any substance contains 6.02 x 10^23 particles.

Hence 0.25 mole of any has will contain 0.25 x 6.02 x 10^23 molecules of that gas

They cannot contain the same no. of atoms as 1 molecule of CO2 contains 3 atoms, 1 molecule H2 contains 2 molecules, and 1 molecule of NH3 contain 4 atoms

1 molecule of any gas will occupy 22.4 L at STP

hence 0.25 mol of all of these gases accupy the same volume

all of these molecules have different molar masses. thus their g. f. w cannot be same

Your answer is that they will occupy the same volume, and the same number of molecules