A gas mixture contains 0.60 mol of N2, 0.10 mol of H2, 0.20 mol of CH4. Calculate the pressure of the gas mixture and the partial pressure of each constituent gas if the mixture is in a 6.0 L vessel at 27C.

Question

What is the:
Total pressure
Pressure of H2
Pressure of N2
Pressure of CH4

THANKS!!

Answer 1

There are a couple ways to do this but both depend upon the same process.
#1 way.
a) Use n = individual mols listed in the problem, use PV = nRT and solve for Peach as pN2, pH2, pCH4.
b) Then find ptotal = pN2 + pH2 + pCH4.

#2 way.
a. Add mols of individual gases to find ntotal, the use PV = nRT and substitute the conditions of the problem; solve for Ptotal (since you used ntotal).

b. Calculate mols fraction of each gas.
You know total mols from above,
XN2 = (pN2/total mols) = ?
XCH4 = (pCH4/total mols) = ?
XH2 = (pH2/total mols)

c. pH2 = XH2*Ptotal
pN2 = XN2*Ptotal
pCH4 = XCH4*Ptotal

#1 is easier because it's all the same formula; #2 is more interesting because you use something different. Mole fraction is important.