How to Calculate Humidity in an Airtight Vessel?

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AI Thread Summary
To calculate humidity in an airtight vessel with a volume of 1m^3 at 45°C and 75% relative humidity, one must determine the internal pressure required to achieve these conditions. The partial pressure of water vapor is essential for calculating relative humidity, which depends on the temperature and the saturation vapor pressure at that temperature. The user is seeking guidance on how to calculate the mass or moles of water vapor needed to find the overall pressure and relative humidity. Understanding the relationship between temperature, pressure, and water vapor content is crucial for solving this problem. The discussion emphasizes the need for foundational equations related to gas laws and vapor pressure to proceed with the calculations.
mahler.ji
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Hello,

This is my first post on here, so thank you in advance for your help.


Homework Statement



I have an air tight vessel that has a volume of 1m^3. The bottom of the vessel has water in it. What internal pressure is needed inside the vessel to achieve a temperature of 45C and 75% Relative Humidity? Also, what is the partial pressure of water vapor at that condition?


Homework Equations



None Given.

The Attempt at a Solution



I can't figure out how to figure out the mass/moles of water vapor in the air in order to figure out partial pressure and, thus, the relative humidity. I can't figure out how to get the overall pressure without knowing the mass/moles of water vapor in the air either. So I just need to know how to get started and i think I can finish it.


again, thanks for your help.
 
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Anyone have any ideas at all?

I think the real question is, based on Temperature and Pressure, how do I know how much water is in the air??

Thanks,
 
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