Using henry's law, calculate the molar concentration of o2 in the surface water of a mountain lake saturated with air at 20 ∘c and an atmospheric pressure of 685 torr .

The molar concentration of oxygen gas in water is .

Explanation:

Partial pressure of the gas = 685 torr = 0.8905 bar

1 torr = 0.0013 bar

According Henry's law:

Value of Henry's constant of oxygen gas at 20 °C in water = 34860 bar

Let the number of moles of gas in 1 liter water be n.

1 Liter water = 1000 g of water

Moles of water in 1 L

Molar concentration of oxygen gas in 1 L of water:

The molar concentration of oxygen gas in water is .