Partial Pressure

Partial Pressure

Partial Pressure

The pressure that is exerted by one among the mixture of gasses if it occupies the same volume by its own is known as Partial pressure. Every gas exerts certain pressure in a mixture. The total pressure of a mixture of ideal gas is the sum of partial pressures of individual gases in the mixture, based on the following equation:


Vx denotes partial pressure of the particular gas.

Px indicates the partial pressure of the gas x.

Vtot denotes the total volume of the mixture.

Nx indicates the amount of gaseous substance.

Ptot denotes the total pressure of the mixture.

Ntot is the total amount of substance in a mixture.

Partial pressure is the measures of the thermodynamic activity of gas molecules. The gasses diffuse and react based on their partial pressures and not concentrations in a gaseous mixture.

Partial Pressure

Dalton's law of partial pressures

According to Dalton’s law of partial pressures, the total pressure exerted by the mixture of gases is the sum of the partial pressure of every existing individual gas, and every gas is assumed to be an Ideal gas.

Ptotal = P1 + P2 + P3

Where P1, P2, P3 are the partial pressures of gas 1, gas 2, and gas 3. Since every gas has an independent behavior, the ideal gas law is used to find the pressure of that gas if its number of moles, the volume of container and temperature is known.

The equality arises because the molecules are so wide apart that there is minimal interaction in an ideal gas. For example, a mixture of ideal gas that consists of Nitrogen, hydrogen, and ammonia.

P = PN2 + PH2 + PNH3


PN2 = Partial pressure of nitrogen

PH2 = Partial pressure of hydrogen

PNH3 = Partial pressure of Ammonia

Partial Pressure

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