Question

in an experiment , hydrogen gas is collected in a burette, over water. The ambient pressure s 1.01 atm and the ambient temperature is 20.0°C. At this temperature the vapour pressure of pure water is 17.5 mm Hg cor 0.023 atm what is the pressure of the hydrogen gas inside the burette?

Answer 1

Step 1

Dalton’s law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual component gases.

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Step 2

Look please at the following drawing:

According to this:

Total pressure = vapor pressure + hydrogen pressure

Pt = Pwv + PH2 => Pt - Pwv = PH2 => 1.01 atm - 0.023 atm = 0.987 atm

Answer: Pressure of hydrogen = 0.987 atm