A carbon dioxide sample weighing 44.0 g occupies 32.68 L at 65°C and 645 torr. What is its volume at STP?

Question

Quizplus · Accepted Answer

Using the ideal gas law equation, PV=nRT, and given the conditions of the sample, we can calculate the number of moles of gas present:
PV=nRT
n=PV/RT=(645 torr)(32.68L)/(62.36 L•torr•K)(65+273.15)K=1.44 mol CO2
At STP (standard temperature and pressure, defined as 0°C and 1 atm), one mole of any gas occupies 22.4 L. Therefore, 1.44 mol of CO2 would occupy:
V=nRT/P=(1.44 mol)(0.08206 L•atm/mol•K)(273.15 K)/(1 atm)= 32.05 L ≈ 22.4 L. 
So the best choice is A, which is 22.4 L.

A Carbon Dioxide Sample Weighing 44