P1.7 Factors Affecting Gas Pressure

• Explain how decreasing the volume of a container affects the pressure of a gas.

  It will increase the pressure. Decreasing the volume of the container, whilst keeping the number of gas particles the same, will increase the concentration. There will also be a smaller distance between the walls.

  These two points mean that collisions between particles of a gas and the walls of the container will be more frequent. This means that more force will be exerted over a smaller area of the container, and so the pressure will be higher.
• Explain how increasing the temperature of a gas in a fixed container will affect the pressure.

  At higher temperatures, the particles will have more kinetic energy.

  This means they will collide with the walls more frequently and with more force, so the pressure will increase.
• How do gas particles trapped in a container behave?

  They move about more randomly, travelling at straight lines until they collide with another particle or a wall, at which point they bounce off.
• Explain how increasing the concentration of a gas in a flexible container (like a balloon) will affect the volume.

  At higher concentrations of particles mean more particles in the same volume. These extra particles will collide with the walls of the container and so push the container walls outwards, increasing the volume.

  This is only possible if the container is flexible, like a balloon (If the container is not flexible, the pressure will increase instead).
• As volume decreases, pressure increases.

  Because of less space, more collisions occur therefore more pressure is exerted.