Question

Zinc metal is added to hydrochloric acid to generate hydrogen gas, which is collected over a liquid whose vapor pressure is the same as pure water at 20.0°C (18 torr). The volume of the gas mixture is 1.7 L and its total pressure is 0.810 atm. Determine the partial pressure of the hydrogen gas in this mixture.

Answer 1

Answer:

The partial pressure of the hydrogen gas is 0.786 atm

Explanation:

In this case, the gas mixture contains the vapor from the liquid, and hydrogen gas. Before we do any calculations, we need to convert 18 torr into atm:

$18torr*\frac{1atm}{760torr} =0.0237atm$

Then we use the equation of Dalton's law, which states that the total pressure of a gas mixture is equal to the sum of the partial pressure of its components:

$P_{T}=P_{H}+P_{v}$

Where $P_{T}$ is the total pressure, $P_{H}$ is the partial pressure of hydrogen, and $P_{v}$ is the partial pressure of the vapor of the liquid.

Replacing the data we know:

0.810 atm= $P_{H}$ + 0.0237 atm

$P_{H}$= 0.786 atm