Question

What volume is occupied by 0.963 mol of `CO_2` at 300.9 K and 913 mmHg?

Answer 1

`V=(nRT)/P` `~=20L`

Explanation:

The only difficulty in solving this problem is getting the appropriate units. The quoted units of pressure are unfortunate. We know that `1` `atm` `-=` `760*mm*Hg`; i.e. that `1*atm` will support a column of mercury `760*mm` high. Thus `P` `=` `(913*mm*Hg)/(760*mm*Hg*atm^-1)` `=` `1.20*atm` (and this measurement should have been quoted in the problem). If you measured pressures with such a mercury column you would end up getting mercury all over the laboratory, so whoever set this question was ignorant, and deserves a bollocking.

Given appropriate units of pressure,

`V=(0.963*molxx0.0821*L*atm*K^-1*mol^-1xx300.9K)/(1.20*atm)` `=` `??L`