Gas Laws Cheat Sheet

Key Facts

• Boyle's law states that pressure and volume are inversely proportional when temperature and moles stay constant: $P_1V_1 = P_2V_2$.
• Charles's law states that volume and temperature are directly proportional when pressure and moles stay constant: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$.
• Gay-Lussac's law states that pressure and temperature are directly proportional when volume and moles stay constant: $\frac{P_1}{T_1} = \frac{P_2}{T_2}$.
• The combined gas law relates pressure, volume, and temperature for a fixed amount of gas: $\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$.
• The ideal gas law relates pressure, volume, moles, and temperature: $PV = nRT$.
• Temperature in gas law calculations must be measured in kelvins, using $T_{K} = T_{^\circ C} + 273.15$.
• Dalton's law of partial pressures states that the total pressure of a gas mixture is the sum of each gas pressure: $P_{\text{total}} = P_1 + P_2 + P_3 + \cdots$.
• At standard temperature and pressure, $1$ mole of an ideal gas has a volume of about $22.4\ \text{L}$ at $273.15\ \text{K}$ and $1\ \text{atm}$.

Vocabulary

Pressure

Pressure is the force of gas particle collisions per unit area, often measured in $\text{atm}$, $\text{kPa}$, or $\text{mmHg}$.

Volume

Volume is the amount of space a gas occupies, usually measured in $\text{L}$ or $\text{mL}$.

Kelvin

Kelvin is the absolute temperature scale used in gas laws, where $0\ \text{K}$ represents absolute zero.

Mole

A mole is an amount of substance equal to $6.022 \times 10^{23}$ particles.

Ideal Gas

An ideal gas is a model gas whose particles have no volume and no intermolecular attractions.

Partial Pressure

Partial pressure is the pressure one gas in a mixture would exert if it occupied the container alone.