A sample of hydrogen gas (H2) is produced in a laboratory by displacement of water. A 645 mL sample of hydrogen is collected at 25 degrees Celsius and a total pressure of 758 torr. Collecting gas by water displacement causes the gas to become saturated with gaseous water vapor. Thus the sample is a mixture, and the water vapor contributes to the total pressure of "wet" hydrogen. The partial pressure of water vapor in such a mixture is given by the vapor pressure of water. A table of experimentally determined water vapor pressures of water shows that the vapor pressure of water at 25 degrees Celsius is 24 torr. Calculate the pressure of the "dry" hydrogen in the mixture.

Question

A sample of hydrogen gas (H2) is produced in a laboratory by displacement of water. A 645 mL sample of hydrogen is collected at 25 degrees Celsius and a total pressure of 758 torr. Collecting gas by water displacement causes the gas to become saturated with gaseous water vapor. Thus the sample is a mixture, and the water vapor contributes to the total pressure of "wet" hydrogen. The partial pressure of water vapor in such a mixture is given by the vapor pressure of water. A table of experimentally determined water vapor pressures of water shows that the vapor pressure of water at 25 degrees Celsius is 24 torr. Calculate the pressure of the "dry" hydrogen in the mixture.

Answer 1

A lot of reading and most is just a description of the experiment. Don't get distracted by all the verbiage.

Ptotal = pH2 + pH2O
You know Ptotal and pH2O. Substitute and solve for pH2(dry).

Answer 2

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Answer 3

To calculate the pressure of the "dry" hydrogen in the mixture, we need to subtract the partial pressure of water vapor from the total pressure.

Given:
Total pressure (Ptotal) = 758 torr
Partial pressure of water vapor (Pwater vapor) = 24 torr

To find the pressure of the "dry" hydrogen (Pdry hydrogen), we use the following equation:

Pdry hydrogen = Ptotal - Pwater vapor

Substituting the given values, we have:

Pdry hydrogen = 758 torr - 24 torr
Pdry hydrogen = 734 torr

Therefore, the pressure of the "dry" hydrogen in the mixture is 734 torr.

Answer 4

To calculate the pressure of the "dry" hydrogen in the mixture, we need to subtract the partial pressure of water vapor from the total pressure.

Given:
Total pressure (Ptotal) = 758 torr
Partial pressure of water vapor (Pwater vapor) = 24 torr

To find the pressure of the "dry" hydrogen (Pdry hydrogen), we can use Dalton's law of partial pressures, which states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas:

Ptotal = Pdry hydrogen + Pwater vapor

Rearranging the equation, we get:

Pdry hydrogen = Ptotal - Pwater vapor

Substituting the given values, we have:

Pdry hydrogen = 758 torr - 24 torr

Calculating this, we find that the pressure of the "dry" hydrogen in the mixture is:

Pdry hydrogen = 734 torr