How do you find the number of grams of #CO_2# that exert a pressure of 785 mmHg at a volume of 325 L and a temperature of 32°C?

1 Answer
Nov 30, 2016

Answer:

Approx. #600*g# of carbon dioxide gas.

Explanation:

We know (or should know) that #n=(PV)/(RT)#, and further that #1*atm-=760*mm*Hg#.

And thus #n=((785*mm*Hg)/(760*mm*Hg*atm^-1)xx325*L)/(0.0821*L*atm*K^-1*mol^-1xx305*K)~=13*mol#.

And #13*molxx44.0*g*mol^-1~=600*g#.

From where did I get the figure #44.0*g*mol^-1#?

My own feeling is that you should never use a column of mercury to measure pressure ABOVE atmospheric pressure. You will end up getting mercury EVERYWHERE. A column of mercury is suitable for measuring LOW pressures. These days, mercury is rarely present in a laboratory due to safety concerns.