Question #5174b

1 Answer
Apr 12, 2017


The mass will be 4429 g


Use the ideal gas law to solve this problem: #PV=nRT#

This law specifies the possible conditions for a sample of gas, and makes it possible for us to find a fourth condition when values are given for the other three.

Here, we know the pressure, P is 135.0 atm. The volume, V is 200.0 L and the temperaure T is 24.00 °C, or better as 297K.

Thus, we can solve for the missing value, which is #n#, the gas quantity in moles.

#n = (PV)/(RT)#

You must be careful to choose a value for the gas constant #R# that matches the units given in the problem. Specifically, since the pressure is in atmospheres, we use #R= 0.0821 ("L atm")/(K" mol")#

#n = ((135)(200))/((0.0821)(297)) = 1107.3# moles

Now, multiply by the molar mass of helium (4 g) and this answer is reported as a mass.