which of the following statements concerning equal volumes of the gases nitogen oxide and sulfer trioxide at?

Question

the same tempertaure and pressure, is true?

1. they have the same number of atoms
2. they have the same number of molecules
3. they have the same density

Answer 1

2

they can't have the same number of atoms if they have the same number of molecules because the sulfur trioxide molecule has more atoms in it

they can't have the same density if they have the same number of atoms because the sulfur trioxide molecule weighs more

they have approximately the same number of molecules (to the extent to which they act ideally) as described in the "gas laws"

PV=nRT

if P and V and T are the same (R is always a constant) then n, the number of moles (directly related to the number of molecules) is also the same

Answer 2

use PV = nRT
Same volumes, temperature and pressures and assuming ideal behaviour implies they have the same number of moles (molecules). However they have different masses (use the chemical formula) hence they have different densities. They can't have the same number of atoms. So it's 2.