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1.2.1.6 Henry’s Law
Henry’s law states that the quantity of the dissolved gas in liquid is proportional to
its partial pressure above the liquid.
Mathematically, Henry’s law is written as:
C
P
equil
g as
= α
Where
C equil  = the concentration of gas dissolved in the liquid at equilibrium.
P gas  = the partial pressure of the gas above the liquid.
α = Henry’s law constant for the gas at the given temperature.
1.2.1.7 Graham’s Law
Graham’s law states that the rates of diffusion of gases are inversely proportional to
the square roots of their densities.
1.2.1.8 Dalton’s Law of Partial Pressure
Dalton’s law of partial pressure states that the total pressure exerted by mixture of
non-reacting gases is equal to the sum of the partial pressures of the individual gases
(Fig. 1.11).
Mathematically,
P
P
P
P
P
total
g as
gas
g as
gasi
=
+
+
+…+
1
2
3
Where P total is the pressure exerted by all gases on a body and P 1 , P 2 , P 3 ,…P i are the
partial pressure exerted by each gas.
→
+
Gas 1
G as 2
Gas 3
Gas 1, 2, 3
P gas1 = 1 atm
P gas1 = 1 atm
P gas1 = 1 atm
P gas1,2,3 = 3 atm
+
Fig. 1.11 Pictorial depiction of Dalton’s law of partial pressure
1 Fundamentals of Chemistry for Environmental and Medical Professionals