A balloon with a volume of #2.00L# is filled with helium gas at a temperature of #27.0˚C# and a pressure of #1.20 atm#. How many grams of helium are in the balloon?

1 Answer
May 28, 2017

Answer:

A mass of approx. #0.4*g# is contained........

Explanation:

Given #n="Mass"/"Molar mass"=(PV)/(RT)#.

#"Mass"=(PV)/(RT)xx"molar mass"#,

.........Agreed........?

And, as is typical, we use the value of..........

#R=0.0821*L*atm*K^-1*mol^-1#

The which has units that chemists typically use. And so we plugs in the numbers:

#"Mass"=(1.2*atmxx2.00*Lxx4.00*g*mol^-1)/(0.0821*(L*atm)/(K*mol)xx300*K)#

#~=400*mg#