A 400.mL sample of hydrogen is collected over water at 23.0^°C and 758.4 torr.What isthe volume of the dry hydrogen gas at 23.0^°C and 758.4 torr? The vapor pressure of water at 23.0^°C is 21.1 torr.

Question

Quizplus · Accepted Answer

To find the volume of dry hydrogen gas, we need to use the formula:

V(Dry Gas) = V(Initial Gas) - V(Water Vapor)

where V(Initial Gas) is the volume of hydrogen collected over water, and V(Water Vapor) is the volume of water vapor at the given temperature and pressure. To find V(Water Vapor), we can use the partial pressure of water vapor:

P(Water Vapor) = 21.1 torr

V(Water Vapor) = (P(Water Vapor) * V(Total Gas)) / P(Total Gas)

V(Total Gas) = P(Total Gas) * V(Initial Gas) / P(Initial Gas)

V(Total Gas) = (758.4 torr) * (400 mL) / (760 torr) = 398.95 mL

V(Water Vapor) = (21.1 torr) * (398.95 mL) / (758.4 torr) = 11.07 mL

Now we can calculate V(Dry Gas):

V(Dry Gas) = (400 mL) - (11.07 mL) = 388.93 mL, which is closest to option B (389 mL).

A 400ML Sample of Hydrogen Is Collected Over Water at 23