Question

If the pressure in the room is 759.2 torr and the vapor pressure of water is 23.8 torr, what is the pressure of hydrogen gas in the collection tube?

Answer 1

Working Principle: Dalton's Law of Partial Pressure

To solve for the pressure of hydrogen gas, we just simply subtract the water vapor pressure to the total pressure.

Pressure of Hydrogen (H2) = Total pressure - H2O vapor pressure
Pressure of Hydrogen (H2) = 759.2 torr - 23.8 torr = 735.4 torr

ANSWER: 735.4 torr

Answer 2

The partial pressure of Hydrogen gas can directly be calculated by simply taking the difference of the overall pressure and the vapour pressure of water. That is:

P (H2 gas) = 759.2 torr – 23.8 torr

P (H2 gas) = 735.4 torr