Question

What is the mole fraction of H_2 in a mixture with a total pressure of 800 torr when the partial pressure of H_2 is 90 torr? a. 1.0 b. 8.8 c. 0.5 d. 0.11 e. 0.88

Answer 1

Answer:

d. 0.11

Explanation:

According to the Dalton's law of partial pressure, the total pressure of the gaseous mixture is equal to the sum of the pressure of the individual gases.  Also, the partial pressure of the gas is equal to the product of the mole fraction and total pressure.

Total pressure, P = 800 torr

Partial pressure of hydrogen gas = 90 torr

So,  

$P_{H_2}=X_{H_2}\times P$

$X_{H_2}=\frac{P_{H_2}}{P}$

$X_{H_2}=\frac{90\ torr}{800\ torr}$

$X_{H_2}=0.11$

Answer 2

Answer:

The correct answer is d) 0, 11

Explanation:

We use Dalton`s Law:

Partial Pressure = Total Pressurex mole fraction

90 torr = 800 torr x mole fraction

Mole fraction = 90 torr/ 800 torr= 0, 1125