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### Topic: Physical Chemistry- Using the integrated Vant Hoff Equation with K values.  (Read 2646 times)

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#### Twickel

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• Gender:  ##### Physical Chemistry- Using the integrated Vant Hoff Equation with K values.
« on: September 25, 2012, 04:36:37 AM »
The equilibrium concentration of oxygen in fresh water exposed to the atmosphere is given for two temperatures. At 15 degrees celcius equilib [O2]= 630μmol/L at 25 degrees celcius equiln [O2]= 517μmol/L

The expression for the equilibrium constant, K, between the oxygen in the gas phase and in solution is given by K=[O2]/PO2/atm. Where pO2 is the partial pressure of atmospheric oxygen.

I need to calculate the enthalpy of dissolution, I figured I need to use the integrated Vant hoff equation.
But how do I figure out the partial pressues of oxygen so I can calculate the equilibrium constants? I know that P= xa x P^*

[Thank you

#### Borek ##### Re: Physical Chemistry- Using the integrated Vant Hoff Equation with K values.
« Reply #1 on: September 25, 2012, 08:16:23 AM »
21% of oxygen in the atmosphere.
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#### Twickel

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« Reply #2 on: September 25, 2012, 08:28:23 AM »
so Kp at 25 degrees is equal to 298/[0.21/1]?
= 1,419

#### Twickel

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« Reply #3 on: September 27, 2012, 03:11:25 AM »
Sorry about that, got mixed up.

Is the Kp value at 25 degrees Kp=[517/0.21/1] = 2461?