Hey this question has me stumped and I could really use some help:

 

What is the activity of liquid water in a multicomponent system in which the vapor pressure of water is 748.2 mmHg at 100.0 degrees Celsius?

 

That is all the information given. I think I am probably missing something obvious here, but every equation I have to find activity requires some other info, ie mole fraction or partial pressure.

 

Any help will be greatly appreciated.

Thanks, RB

you have the partial pressure of water.

i have the vapor pressure of the pure liquid, not the partial pressure in the system...i think

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i would need the mole fraction to find the partial pressure using Raoult's law

it says the vapour pressure of water in the system is 748.2 mmHg this is it partial pressure.

 

if it was pure water at 100*C then it would be 760mmHg

lol like i said i was missing something obvious. im an idiot, been studying since 10am.

thanks a lot, sir