Calculate the solubility of argon in water at an atmospheric pressure of 0.370 atm (a typical value at high altitude).

Gas Mole Fraction kH mol/(L*atm)
N2 7.81 x 10-1 6.70 x 10-4
O2 2.10 x 10-1 1.30 x 10-3
Ar 9.34 x 10-3 1.40 x 10-3
CO2 3.33 x 10-4 3.50 x 10-2
CH4 2.00 x 10-6 1.40 x 10-3
H2 5.00 x 10-7 7.80 x 10-4

4.84 × 10⁻⁶ M

Explanation:

First, we will calculate the partial pressure of Ar (pAr) using the following expression.

pAr = P × χAr

where,

P: total pressure

χAr: mole fraction

pAr = P × χAr

pAr = 0.370 atm × 9.34 × 10⁻³

pAr = 3.46 × 10⁻³ atm

We can find the solubility of Ar in water (S) using Henry's law.

S = kH × pAr

where

kH: Henry's constant

S = kH × pAr

S = 1.40 × 10⁻³ M/atm  × 3.46 × 10⁻³ atm

S = 4.84 × 10⁻⁶ M