# Dalton's Law

## Gibbs' Dalton's law of the total pressure of a mixture of gases.

The total pressure of a mixture of gases is made up by the sum of the partial pressures of the components in the mixture - also known from Gibbs'-Dalton's Law of Partial Pressures.

*the total pressure exerted by a mixture of gases is the sum of the partial pressures of the individual gases*

The total pressure in a mixture of gases can be expressed as:

p_{total}= p_{1}+ p_{2}+ .. + p_{n }

= Σp_{i}(1)

where

p_{total}= total pressureof mixture (Pa, psi)

p_{i}= partial pressure of individual gas (Pa, psi)

Assuming that each gas behaves ideally - the partial pressure for each gas can calculated from the Ideal gas Law as

*p _{i} = n_{1} R T / V (2)*

*where *

*n _{1} = the number of moles of the gas*

*R = universal gas constant (J/(mol K), lb _{f} ft/(lb mol ^{o}R), 8.3145 (J/(mol K))*

*T = absolute temperature (K, ^{o}R)*

*V = volume (m ^{3}, ft^{3}) *