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?

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

1 Answer
Jan 22, 2017

"Molar mass"Molar mass ~= 66*g*mol^-166gmol1

Explanation:

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

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

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

And thus "Molar mass"Molar mass == "Mass of gas"/(PV)xxRT=Mass of gasPV×RT=

(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.