Question

A sample of hydrogen gas is collected over water at 25°C. The total pressure of the hydrogen and water vapor is 116.0 kPa. The partial pressure of water vapor at this temperature is 3.2 kPa. What is the pressure of the hydrogen gas alone?

Answer 1

112.8 kpa, the reason for this is you subtract 3.2 Kpa from 116.0kpa and that's the answer.

Answer 2

Answer: The pressure of hydrogen alone is 112.8 kPa.

Explanation:

According to Dalton's law, the total pressure of a mixture of gases is the sum of individual pressures exerted by the constituent gases.

$p_{total}=p_A+p_B$

Thus $p_{total}=p_{H_2O}+p_{H_2}$

Given: $p_{total}=116.0 kPa$

$p_{H_2O}=3.2kPa$

$p_{H_2}= ?kPa$

Thus $116.0kPa=3.2kPa+p_{H_2}$

$p_{H_2}=112.8kPa$