You collect hydrogen gas over water at 323 K. The partial pressure of hydrogen is 122.4, and the total pressure is 134.7 kPa. What is the pressure of the water vapor

12.3kPa

Explanation:

Using Dalton's law which states: in a mixture of gases the total pressure is equal to the sum of the pressures of all gases present. In this question,

Total Pressure = Pressure of Hydrogen + Pressure of water vapor

Pressure of Hydrogen = 122.4kPa

Total Pressure 134.7kPa.

Pressure of water vapor = Total pressure - Pressure of Hydrogen =

134.7kPa - 122.4kPa = 12.3kPa.

Vapor pressure of water at certain temperatures is is usually available in vapor pressure table. In this question temperature here is 323 K.

Convert 323 K to celsius (using the formula Celsius = K - 273) will give us 323 k - 273 = 50 degrees celsius. Checking the vapor pressure of water at 50 degrees celsius will show you 12.34kPa