Gases :  Laws

Boyle's Law
  • The Pressure (P) of a gas is inversely proportional to Volume (V) at constant

  • Temperature (T) and moles of gas (n). 
Robert Boyle
  • The product of pressure and volume of one measurement is equal to the product 
  • of the pressure and volume of another measurement. 
                              P1V1 = P2V2

Amonton's Law

Charles' Law
  • The Volume of a gas is directly proportional to the Temperature (Kelvin) 

  • at constant P and n. 
César Charles

Gay-Lussac's Law(law of combining volumes)
  • The ratio of the volumes of gases consumed or produced in a chemical reaction is

  • equal to the ratio of simple whole numbers (coefficients in the balanced equation). 
      e.g.  Carbon monoxide combines with oxygen in a 2:1 ratio by volume 
Joseph Louis

Avogadro's Hypothesis
  • The Volume of a gas is directly proportional to the moles of the gas, n at constant P and T. 
  • The hypothesis that equal volumes of different gases at the same temperature

  • and pressure contain the same number of particles. 
  Amadeo Avogadro

Dalton's Law of Partial Pressures
  • The total pressure of a mixture of gases is equal to the sum of the partial pressures of the various components. 
  • Partial Pressure - The fraction of the total pressure of a mixture of gases that results from one component of the mixture. 
    This Law can be used to correct the amount of water vapor picked up when a gas is collected by displacing water. 
    • Vapor Pressure - The pressure of the gas that collects above a liquid in a closed container. 
  John Dalton
Next:  "Ideal Gas Equation"