Dalton's Law Of Partial Pressure

Dalton's Law Of Partial Pressure

PAY-LOAD

When a balloon is buoyant, it can take along some weight into the upper atmosphere. The maximum weight a balloon can carry along is called its pay-load.

Pay load = weight of the air displaced − (weight of the balloon + weight of the gas it contains)

DALTON’S LAW OF PARTIAL PRESSURE

The relation between the pressures of the mixture of non−reacting gases enclosed in a vessel to their individual pressure is described in the law. The law was given by John Dalton in 1807. It states that.

At constant temperature, the pressure exerted by a mixture of two or more non−reacting gases enclosed in a definite volume, is equal to the sum of the individual pressures which each gas would exert if present alone in the same volume.

The individual pressures of gases are known as partial pressures.

If P is the total pressure of the mixture of non−reacting gases at temperature T and volume V, and P1, P2, P3 …. represent the partial pressures of the gases, then

P = P1 + P2 + P3+ ……… (T, V are constant)

Partial Pressure in terms of Mole Fraction

Mole fraction χ defines the amount of a substance in a mixture as a fraction of total amount of all substances. If n=1 moles of way substance is present in n moles of the mixture, then mole fraction of the substance, χ1 = n1/n

If PN2 is the partial pressure of nitrogen the mixture of SO2 and N2. Then

(n_N2 = no. of moles of N2)

and Pmixture =

dividing we get,