A mixture of H2 and water vapor is present in a closed vessel at 20°C. The total pressure of the system is 755.0 mmHg.

Partial pressure of water vapor at 20°C equals 17.5 mmHg.

What is the partial pressure of H2?

737.5 mmHz

Huh ? subtract

To find the partial pressure of H2, we need to subtract the partial pressure of water vapor from the total pressure of the system.

Partial pressure of H2 = Total pressure - Partial pressure of water vapor

Partial pressure of H2 = 755.0 mmHg - 17.5 mmHg

Partial pressure of H2 = 737.5 mmHg

Therefore, the partial pressure of H2 is 737.5 mmHg.