Question

Question #74d82

Answer 1

You divide molar mass by molar volume.

Explanation:

Molar mass for `HCl` is (rounded) `1.0+35.5=36.5g//mol`
(you can get more exact figures from any source).

Molar volume at `273Kand1atm=22.4dm^3//mol`

So `HCl` has a density of:

`rho=(36.5g//cancel(mol))/(22.4dm^3//cancel(mol))=1.63g//dm^3=1.63kg//m^3`

Note : There are many STP conditions defined. I used the one that is most common in my country.