Answer to Question #267171 in General Chemistry for Zai

Question

A 1.50 L bulb containing He at 155 torr is connected by a valve to a 2.00 L bulb containing CH4 at

245 torr. The valve between the two bulbs is opened and the two gases mix.

a. What is the partial pressure (torr) of He and CH4?

b. What is the mole fraction of He?

Answer 1

a) Partial pressure of He

P₁V₁ = P₂V₂(155 torr) (1.50 L) = (x) (3.50 L)

x = 66.4 torr

Partial pressure of CH₄:

(245 torr) (2.00 L) = (y) (3.50 L)

y = 140. torr

b) Total pressure:

66.4 torr + 140. torr = 206.4 torr

Mole fraction of He:

66.4$/$ 206.4 = 0.322