At a constant temperature, the amount of a given gas dissolved in a given type
and volume of liquid is directly proportional to thepartial
pressureof that gas in equilibrium
with that liquid.
P=pressure of the gas (atm) K=Henry's Law Constant (atm/M)
C=Concentration of the
Henry's law constant for He gas in water at 30°C is 2.70 x 103 atm/M.
The constant for N2 at the same temperature is 1.67 x 103
atm/M. If the two gases are each present at 1.43 atm pressure, calculate the
solubility, in M, of each gas.
P=KC or P/K=C
/ 2.70x103 atm = 5.30 x10-4 Molar
1.43 atm/ 1.67 x 103 atm = 8.56 x10-4 Molar
***Watch the units
some chemist use the equation S=KP (solubility= Henrys constant x
Henrys constant will have the units of
M/atmfor this equation
Henry's Law constant for the solubility of nitrogen in water is 6.40x10^-4 M/atm
at 25.0 Celsius. At .750 atm how many grams of N2 can be dissolved in
.250 L of water at 25.0 degrees Celsius
= (6.40 x 10^-4 M/atm)*(0.750 atm) = 4.8 x 10^-4 M