Question

Select all that apply. At STP conditions, 0.50 moles of CO(g), Cl2(g), O2(g): will contain the same number of molecules, will contain the same number of atoms, will occupy the same volume, will have the same g.f.w.

Answer 1

1 mol is (always) the same number of units: 6.02 * 10^23 units.


So 0.5 moles  of any gas has the same number of molecules.


Also, we know by the ideal gas laws that a give number of molecules of any gas will occupy the same volume.


Given that the three gases have the same number of atoms in the molecular fomula (2), 0.5 moles will also have the same number of atoms.


g.f.w. stands for grams formula weight and that is different for all of them, because gfw is calcualted from the atomics masses of each atom in the molecule.


Then at STP (standard temperature and pressure) conditions 0.50 moles of any of the gas:


- will contain the same number of molecules,

- will contain the same number of atoms

- will occupy the same volume.