Question

When a chemist collects hydrogen gas over water, she ends up with a mixture of hydrogen and water vapor in her collecting bottle If the pressure in the collecting bottle is 97.1 kilopascals and the vapor pressure of the water is 3 2 kilopascals, what is the partial pressure of the hydrogen?

Answer 1

Answer: 93.9 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: $p_{total}=97.1 kPa$

$p_{H_2O}=3.2kPa$

$p_{H_2}= ?kPa$

Thus $97.1kPa=3.2kPa+p_{H_2}$

$p_{H_2}= 93.9kPa$