Using Henry's Law, Calculate percentage (by volume) of Oxygen and Nitrogen in air dissolved in water?

Using Henry's Law, Calculate percentage (by volume) of Oxygen and Nitrogen in air dissolved in water at 25C. The air in equilibrium with water at 1 bar pressure may be considered to be 20% oxygen and 80% nitrogen by volume



Henry constant for oxygen: 4.40 x 10^9 Pa

Henry constant for nitrogen: 8.68 x 10^9 PaUsing Henry's Law, Calculate percentage (by volume) of Oxygen and Nitrogen in air dissolved in water?
The solubility of oxygen in water is higher than the solubility of nitrogen.



Answer : Air dissolved in water contains approximately 35.6% oxygen compared to 21% in air.

That means the nitrogen would be about 64.4% of the air that is dissolved in the water, compared to about 79% in regular air.



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Henry Law's Constants at a system temperature of 25C

* Oxygen - O2 : 756.7 atm/(mol/l) = 4.40 x 10^9 Pa

* Nitrogen - N2 : 1600 atm/(mol/l) = 8.68 x 10^9 Pa

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Oxygen dissolved in the Water at atmospheric pressure can be calculated as:



co = (1 atm) 0.21 / (756.7 atm/(mol/liter)) (31.9988 g/mol)



= 0.0089 g/liter

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Nitrogen dissolved in the Water at atmospheric pressure can be calculated as:



cn = (1 atm) 0.79 / (1600 atm/(mol/liter)) (28.0134 g/mol)



= 0.0138 g/liter