Lesson 13-14: Dalton's Law of Partial Pressure

•Gas pressure

is the force from particle collisions on container walls. lt results from particles hitting the walls, creating outward force. In a gas mixture, total pressure comes from all particle

collisions.

Partial pressure

is the pressure from one specific gas.

Dalton's Law:

Total pressure = sum of all partial pressures.

Partial Pressure an Dalton's Law

Dalton's Law says that the partial pressures of each gas in a mixture simply add up to the total

pressure of the mixture.

Partial Pressures and Mole Fractions

In chemistry, a mole fraction is the (unitless) ratio of the moles of a component in a mixture to the moles of every component in the mixture.

a mole fraction

is the proportion of one component in a mixture

Importantly, in a gas mixture,

a gas mole fraction equals the ratio between its partial pressure and the total pressure.