The total pressure in a vessel containing hydrogen collected over water at 25.0°C was 0.8 atm. The vapor pressure of water at that temperature is 23.8. what was he pressure of the oxygen in torr?

Ptotal = pO2 + pH2O

I would convert 0.8 atm to torr, substitute into Ptotal and solve for pO2 (in torr).

To find the pressure of oxygen in torr, we need to first determine the partial pressure of hydrogen in the vessel.

The partial pressure of hydrogen can be calculated using Dalton's Law of Partial Pressures, which states that the total pressure in a mixture of non-reacting gases is equal to the sum of the partial pressures of each gas.

In this case, the total pressure in the vessel is given as 0.8 atm, and we know the vapor pressure of water at 25.0°C is 23.8 torr. Therefore, the partial pressure of hydrogen can be found by subtracting the vapor pressure of water from the total pressure:

Partial pressure of hydrogen = Total pressure - Vapor pressure of water
= 0.8 atm - 23.8 torr

To perform the calculation, we need to convert units for the pressure to ensure they are in the same units. Let's convert the total pressure from atm to torr:

Partial pressure of hydrogen = (0.8 atm) x (760 torr / 1 atm) - 23.8 torr
= 608 torr - 23.8 torr
= 584.2 torr

Now that we have the partial pressure of hydrogen, we know that the total pressure is the sum of the partial pressures of hydrogen and oxygen. Therefore, the pressure of oxygen can be found by subtracting the partial pressure of hydrogen from the total pressure:

Pressure of oxygen = Total pressure - Partial pressure of hydrogen
= 0.8 atm - 0.584 atm

Now, we need to convert the pressure of oxygen from atm to torr:

Pressure of oxygen = (0.8 atm - 0.584 atm) x (760 torr / 1 atm)
= 0.216 atm x 760 torr
= 164.16 torr

Therefore, the pressure of oxygen in torr is 164.16 torr.