Dalton's law of partial pressures states that the total pressure of a mixture of gases equals the sum of the pressures that each gas would exert if it was present alone. The pressure exerted by one gas in a mixture of gases is the partial pressure of that individual gas. This law assumes that the gases do not react with each other, but that each gas is a separate component of the system.

Dalton's law of partial pressures can be mathematically expressed by the following. If P_t is the total pressure of a mixture of gases and P₁, P₂, etc. are the pressures that each gaseous component would exert by itself, then the total pressure is given by P_t = P₁ + P₂ + etc. Dalton's law of partial pressures tells us that each gas behaves independently of the other gases...