Gas Laws

Gas Properties

• Indefinite Shape

• Can expand/compress

• Low density

• Diffuse through their containers

Atmospheric pressure

• Continuously move on, strike surface of container

  • Dependent on: # of collisions and nrg of the molecules

Variables affecting the gas pressure

• Increase/Decrease: Volume, Temperature, Number of moles in container

Boyle’s Law

• When pressure goes up, volume goes down (vice versa) w/ constant temp

  • P₁V₁ = P₂V₂

Charles Law

• When temp goes up, volume goes up (vice versa) w/ constant pressure

  • V₁÷T₁ = V₂÷T₂

Gay-Lussac’s Law

• When pressure goes up, temp goes up (vice versa), w/ constant volume

  • P₁÷T₁ = P₂÷T2

Avogadro’s Law

• Volume is related to the moles (n) of gas

  • V₁÷n₁ = V₂÷n₂

Graham’s Law of Effusion

• Rate of Gas 1 ÷ Rate of Gas 2

  • √M₂ ÷ √M₁

Combined Gas Laws

• P, V, and T all change together

  • P₁V₁ ÷ T₁ = P₂V₂ ÷ T₂

Ideal Gas

• Behavior: P & Gas = 0, Absolute temp = 0 C° = 273.15 K

• Equation: PV = nRT

  • P= pressure, V=volume, n=# of moles, R=0.08206, T= temp

• Density Equation: D = PM ÷ RT

  • M = mass/molar mass

• Molar Mass: PV= mRT ÷ M

  • P= pressure, V=volume, m=mass, R=R, T= temp, M= Molar Mass

Dalton’s Law

• Total pressure (P_t) is equal to the sum of each individual gas

  • P_t = P₁ + P₂ + P₃…