Question

Help Jove A sample of propane, a component of LP gas, has a volume of 35.3 L at 315 K and 922 torr. What is its volume at STP? (R= 0.08206L • atm/K • mol, 1 atm = 760 torr) Multiple Choice Ο Ο Ο Ο Ο

Answer 1

Ideal Gas equation is PV=nRT where Pressure(P) is in atms, Volume(V) is in litres, n is number of moles of gas, R is gas constant and Temperature(T) in Kelvin.

For the question

• Pressure(P) = 922torr, we need to convert this in atm. 1 atm is equivalent to 760 torr or we can say 1 torr is equivalent to (1/760)atm. So 922torr is equivalent to 922*(1/760)atm. Therefore, P = 1.2131atm
• Volume(V) = 35.3Litres
• R= 0.08206 L.atm/K
• Temperature(T) = 315K
• We have to find n

Applying ideal gas equation,PV=nRT ⇒ 1.2131*35.3=n*0.08206*315 ⇒ n = 1.6566 moles

Now we need to find volume of n=1.6566moles of gas at STP. STP stands for Standard Temperature and Pressure i.e. Pressure(P) = 1atm and Temperature(T) = 0 degree Celsius = 273.15K. Let Volume be V at STP.

Again applying ideal gas equation, PV=nRT ⇒ 1*V=1.6566*0.08206*273 ⇒V=37.11 L

So Volume at STP is 37.1L.