Gas Laws

• The temperature of a gas is directly proportional to the average kinetic energy of its particles.
• The pressure of a gas is directly proportional to the number of collisions per unit area.
• The volume of a gas is directly proportional to the number of particles.
• Robert Boyle (1627 - 1691) proposed Boyle's Law, which states that pressure is inversely proportional to the volume of a gas at constant temperature.
• Boyles's Law states that pressure is inversely proportional to the volume of a gas at constant temperature.
• Jacques Charles (1746 - 1823) proposed Charles' Law, which states that volume is directly proportional to temperature at constant pressure.
• Kinetic molecular theory

  1. Gases are composed of molecules. The distances from molecule to molecule are far greater than the molecules' dimensions. These molecules can be considered as spherical bodies which possess negligible mass and volume.
• Lorenzo Romano Amadeo Carlo Avogadro (1776-1856) - Italian chemist who discovered that the volume of a gas is directly proportional to the number of molecules in it when temperature and Pressure are held constant.
• Avogadro's Principle states that the volume of a gas is directly proportional to the number of molecules in it when temperature and pressure are held constant.
• Ideal Gas Law is the combination of Boyle's Law, Charles' Law, and Avogadro's law, which states that the pressure of a gas is directly proportional to its volume and inversely proportional to its temperature.
• Kinetic Molecular Theory

  2. Gas molecules are in constant random motion and they frequently collide with each other and with the walls of the container.
• Collisions among molecules are perfectly elastic, where energy may transfer from molecule to molecule but the total energy remains constant,
• Kinetic Molecular Theory

  3. There is a negligible attractive or repulsive force between/among gas molecules.
• Kinetic Molecular Theory

  4. Movement of gas molecules is affected by temperature. KE is directly related to its temperature.
• Boyle's Law


  Deals with the relationship between the pressure and volume of a gas at constant temperature
• Boyle's Law


  • Can be derived from the kinetic theory of gases, which states that gases consist of tiny particles (atoms or molecules) in constant, random motion
  • As the volume decreases, the gas particles collide more frequently with the container walls, leading to an increase in pressure to maintain equilibrium
• Charles's Law


  Deals with the relationship between the volume and temperature of a gas at constant pressure
• If we increase the temperature

  The average kinetic energy of the gas particles increases, causing the gas particles to move faster and exert greater pressure on the container walls, leading to an expansion of the gas volume
• Gay-Lussac's Law


  Deals with the relationship between the pressure and temperature of a gas at constant volume
• If we increase the temperature

  The gas particles will collide more frequently with the container walls, exerting greater pressure to maintain equilibrium
• Avogadro's Law


  Deals with the relationship between the volume and number of moles of a gas at constant temperature and pressure
• If we add more gas to the container

  The volume of the gas will increase to accommodate the additional gas particles
• Combined Gas Law


  A combination of Boyle's Law, Charles's Law, and Gay-Lussac's Law, describing the relationship between pressure, volume, and temperature of a gas when the amount of gas remains constant
• Ideal Gas Law


  A fundamental equation of state for an ideal gas, combining the properties of gases into a single equation
• Ideal Gas Law


  • Gas particles have negligible volume compared to the volume of the container
  • Gas particles exert no intermolecular forces on each other (ideal gas assumption)
  • Gas particles are in constant, random motion, and collisions are perfectly elastic
• The Ideal Gas Law describes how the pressure, volume, temperature, and number of moles of a gas are related under ideal conditions
• Joseph Louis Gay-lussac's proposed the idea of Gay-lussac's Law where P is directly proportional to T at constant V