Question

A gas mixture for use in some lasers contains 5.00 % by weight HCl, 1.00 % H2, and 94 % Ne. The mixture is sold in cylinders that have a volume of 49.0 L and a pressure of 13300 kPa at 21.0 ∘C

What is the partial pressure (in kilopascals) of each gas in the mixture?

Answer 1

if this is by mass, then

assume 100 g basis, so

5 g of HCl

1 g of H2

94 g of Ne

change to mol

mol of HCl = 5/36.5 = 0.13698

mol of H2 = 1/2 = 0.5

mol of Ne = 94/20.1797 = 4.6581

now..

mol frac. of HCl = mol of HCl/Total mol = 0.13698/(0.13698+0.5 + 4.6581) = 0.02586

mol frac. of H2 = mol of HCl/Total mol = 0.5 /(0.13698+0.5 + 4.6581) = 0.09442

mol frac. of Ne = mol of HCl/Total mol = 4.6581/(0.13698+0.5 + 4.6581) = 0.8797

P-partal

P-HCl = mol frac. of HCl * PTotal = 0.02586*13300 = 343.938kPa

P-H2 = mol frac. of H2* PTotal = 0.09442*13300 = 1255.786kPa

P-Ne= mol frac. of Ne* PTotal = 0.8797*13300 = 11700.01kPa