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Offline kdbmvp

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Calculate solubility of gases
« on: February 21, 2019, 05:25:48 AM »
Hello,

How much N2 can be solved in 1L of water at 20 celsius, 1 atm total pressure, if the partial pressure of the N2 gas is 0.78atm? From a table I found that the solubility of N2 in water at 20 celsius is 0.0190 g/L, at a total pressure of 1 atm. The solution manual calculates it this way:
0.78atm*0.0190 g/L = 0.01482 g/L. But is this correct? From how I understand the task the answer should just be 0.0190 g/L

Offline Enthalpy

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Re: Calculate solubility of gases
« Reply #1 on: February 21, 2019, 06:10:37 AM »
What does this "total pressure" mean? If it's 1atm of air, then 0.78atm of N2 is reasonable. If it's 1atm of N2, you need to scale down to 0.78atm.

Offline kdbmvp

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Re: Calculate solubility of gases
« Reply #2 on: February 21, 2019, 07:09:27 AM »
Total pressure was probably the wrong word. It just says: how much N2 can be solved in 1L of water at 20 celsius and 1 atm pressure. Not sure if I entirely understood your answer?

Offline Borek

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Re: Calculate solubility of gases
« Reply #3 on: February 21, 2019, 09:30:27 AM »
Total pressure was probably the wrong word. It just says: how much N2 can be solved in 1L of water at 20 celsius and 1 atm pressure. Not sure if I entirely understood your answer?

Amount of nitrogen dissolved will depend on the partial pressure of nitrogen, other gases don't matter (or rather: effect of their presence ins negligible). What is the partial pressure of nitrogen?
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Offline kdbmvp

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Re: Calculate solubility of gases
« Reply #4 on: February 22, 2019, 06:53:23 AM »
The partial pressure of N2 is 0.78 atm

Offline Borek

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Re: Calculate solubility of gases
« Reply #5 on: February 22, 2019, 02:46:14 PM »
As Enthalpy wrote: assuming the data given was solubility for 1 atm of nitrogen, you should scale the solubility to 0.78 atm (remembering what Henry's law says).
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