Partial Pressure

What is Partial Pressure?

Partial Pressure is defined as if a container filled with more than one gas, each gas exerts pressure. The pressure of anyone gas within the container is called its partial pressure

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


  • Vx denotes the 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

Partial Pressure

Ideal Gases and Partial Pressure

Ideal gas behavior allows gas mixtures to be specified simply. In particular, the ideal gas law holds for each component of the mixture separately. Each component exerts its own pressure referred to as its partial pressure.

Partial pressure is the measure 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 Pressure

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.

Dalton's law of partial pressures

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

P = PN2 + PH2 + PNH3


Partial Pressure

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