Question

Question #01990

Answer 1

You may compare molecular masses, as all gasses have the same number of molecules in a certain volume. At STP 0 deg C and 1 Bar one mole of gas has a volume of 22.4 L.

Explanation:

Molar masses in `g//mol`:
`Ne=20.18`
`N_2=2xx14.01=28.02`
`NH_3=14.01+3xx1.008=17.03`
`CO=12.01+16.00=28.01`

Ranking the densities from low to high:
`NH_3-Ne-CO-N_2`

You could calculate the densities by dividing molar mass by molar volume, though this is not necessary to solve the problem.
E.g. `NH_3: rho=17.03/22.4=0.760g//L=0.760kg//m^3`