A sample of 3.0 grams of an ideal gas at 127°C and 1.0 atmosphere pressure has a volume of 1.5 liters. What is the molar mass of the gas?

Question

The ideal gas constant R, is 0.08 (Latm)/(moleK)?

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Answer 1 · 2017-01-22T08:55:12

#"Molar mass"# #~=# #66*g*mol^-1#

We can use the Ideal Gas equation to give us the molar quantity.

#n=(PV)/(RT)#,

i.e. #"Mass"/"Molar mass"="Amount of substance in moles"= (PV)/(RT)#.

And thus #"Molar mass"# #=# #"Mass of gas"/(PV)xxRT=#

#(3.0*gxx0.0821*cancelL*atm*cancel(K^-1)*mol^-1xx400cancelK)/(1*cancel(atm)xx1.5*cancelL)#

#=??g*mol^-1#.

This is dimensionally consistent, in that all the units EXCEPT #g*mol^-1# cancel out.