Henry's gas law postulates that at constant temperature there is a direct proportionality of the amount of gas that can be dissolved in a given volume and type of liquid to the partial pressure of the gas in equilibrium with the solvent. The constant of proportionality is called Henry's law constant and depends on the type of gas, type of liquid and temperature. Henry's gas law wiki article

Solve for	Equations
kH,px
x
P
kH,pc
C
kH,cp
Caq
Cgas
kH,cc

Pressure (P)		atmosphere (standard) atmosphere (technical) bar barye (cgs unit) centimetre of mercury centimetre of water (4 C) foot of mercury (conventional) foot of water (39.2 F) inch of mercury (conventional) inch of water (39.2 F) kilogram-force per square millimetre kip per square inch micron (micrometre) of mercury millimetre of mercury millimetre of water (3.98 C) pascal (SI unit) pieze (mts unit) pound per square foot pound per square inch poundal per square foot short ton per square foot torr
Concentration (C)		mol/L
Concentration (Caq)		mol/L
Concentration (Cgas)		mol/L
Mole fraction of gas (x)
Henry's law constant (kH,cc)	O2 - 3.18e-2 H2 - 1.91e-2 CO2 - 8.32e-1 N2 - 1.49e-2 He - 9.05e-3 Ne - 1.10e-2 Ar - 3.43e-2 CO - 2.32e-2
Henry's law constant (kH,cp)	O2 - 1.28e-8 H2 - 7.70e-9 CO2 - 3.36e-7 N2 - 6.02e-9 He - 3.65e-9 Ne - 4.44e-9 Ar - 1.38e-8 CO - 9.38e-9	mol/L*Pa
Henry's law constant (kH,pc)	O2 - 7.79e+7 H2 - 1.30e+8 CO2 - 2.98e+6 N2 - 1.66e+8 He - 2.74e+8 Ne - 2.25e+8 Ar - 7.24e+7 CO - 1.07e+8	L*Pa/mol
Henry's law constant (kH,px)	O2 - 4.32e+9 H2 - 7.19e+9 CO2 - 1.65e+8 N2 - 9.20e+9 He - 1.52e+10 Ne - 1.25e+10 Ar - 4.01e+9 CO - 5.91e+9	Pa