Question

In a mixture of argon and hydrogen, occupying a volume of 1.18 l at 894.6 mmhg and 44.1oc, it is found that the total mass of the sample is 1.25 g. what is the partial pressure of argon?

Answer 1

To solve the question, there is a need to use the equation:

PV = nRT

(894.6/760) × 1.18 = n × 0.0821 × (273 + 44.1)

By solving we get:

Total moles, n = 0.053

Assume, the moles of argon as a and of hydrogen as b,

So,

40 × a + 2 × b = 1.25 --------- (i)

a + b = 0.053 ------- (ii)

By solving i and ii we get:

a = 0.03,

Thus, mole fraction of Ar = XAr = 0.03/0.053 = 0.57

So,

Partial pressure of Ar = 894.6 × XAr = 894.6 × 0.57 = 509.92 mm Hg