Question

A chemist collects a sample of H2S (g) over water at a temperature of 250 C. The total pressure of the gas that has displaced a volume of 25 mL of water is 200.30 kPa. What is the pressure of the H2S gas collected?

Answer 1

To determine the pressure of the H2S gas collected, we need to subtract the vapor pressure of water at 25°C from the total pressure measured. The vapor pressure of water at 25°C is 3.17 kPa.

So, the pressure of the H2S gas collected can be calculated as follows:

The pressure of H2S gas = Total pressure - Vapor pressure of water

The pressure of H2S gas = 200.30 kPa - 3.17 kPa

Pressure of H2S gas = 197.13 kPa

Therefore, the pressure of the H2S gas collected is 197.13 kPa.