How do you calculate the number of mol of a gas that is present in a 5.67 L container at 44.7 C, if the gas exerts a pressure of 614.0 mmHg.?

1 Answer
Aug 19, 2016

Answer:

#n=(PV)/(RT)# #~=0.17*mol#

Explanation:

#n=(PV)/(RT)# #=# #(((614*mm*Hg)/(760*mm*Hg*atm^-1)xx5.67*L))/(0.0821*L*atm*K^-1*mol^-1xx317.9*K)#

#~=0.17*mol#

This simply an application of the Ideal Gas Equation. Units of pressure are always a problem, because these units dictate the choice of gas constant, #R#. The most convenient unit of pressure is still the #"atmosphere"#, and this is a unit that is very intuitive. Given this, most chemists would use #mm*Hg#, knowing that #760*mm*Hg-=1*atm#, or rather that #1# #atm# of pressure will support a column of mercury that is #760*mm# high. And thus conversion of #mm*Hg# to #"atmospheres"# makes the choice of gas constant easy.