Gas Laws

Boyles Law

At a constant temperature, pressure and volume are inversely proportional. (As the pressure of gas increases, the volume decreases)

Math eqn for Boyles Law

P1V1=P2V2

Graph for Boyles Law

Examples of Boyles Law

As you squeeze a balloon, the volume decreases but pressure increases

Charles Law

The volume of a gas is directly proportional to its temperature, provided the pressure remains constant

Math Eqn for Charles Law

V1/T1=V2/T2

Charles Law graph

Example of Charles law

When dough is baked, the gas trapped inside heats and expands, so the dough rises

Guy Lussac's Law

The pressure of a gas is directly proportional to its temperature, provided the volume remains constant

Math Eqn For Guy Lussac's Law

P1/T1=P2/T2

Guy Lussac's Law Graph

Guy Lussac's Law example

Tire air pressure drops on a cold day and increases on a hot day

Avogadros Law

The volume of a gas is directly proportional to the number of molecules (or moles) present, assuming the temperature and pressure remain constant

Avogadros Law eqn

V1/n1=V2/n2

Avogadros Law graph

Example of Avogadros Law

When inhaling, you expand your lungs, making room to take in a larger volume of oxygen molecules

Grahams Law

The rate at which a gas diffuses or effuses is inversely proportional to the square root of its molar mass

(under same temp and pressure, lighter gas molecules move faster than heavier ones)

Grahams Law equation

Grahams Law example

Because helium is much lighter, its molecules move faster and it will effuse (escape through the microscopic pores of the rubber) much faster than the heavier nitrogen/oxygen in the air-filled balloon