vapor pressure of water (kinetics)

feiyangflash

Hi All,

I tried to collected hydrogen gas generated from the reaction between a metal and hydrochloric acid. I put a inverted conical flask in the water, and the generated H2 would push the water out of the flask, and then the H2 was collected. However, I guess there is water vapor mixed together with the H2, and therefore the gas volume I read is actually for the summation of H2 and water vapor, rather than the H2. I could find the equilibrium vapor pressure of water at room temperature. However, I don't know whether the equilibrium between liquid water and water vapor is reached or not. The whole reaction last for 1/2 hour.

Is there a way to figure out how much the pressure contributed by water vapor is?

Thank you!

Fei

uby

could you simply use a desiccant to get rid of the water vapor?

if, as you suggest, that there may be a non-equilibrium amount of water vapor in your system, it would be difficult to attach a numerical value to how much is present.

feiyangflash

Thank you for the reply!

I keep it for much longer time, so the equilibrium between the water vapor and liquid water is reached, and then I know how much water vapor there is in the mixed gas of hydrogen and water vapor.