P1.6 Pressure

• What is the formula for pressure?

  Pressure = Force/Area
• How would you describe pressure in words?

  Pressure is a measure of the force per unit of area.
• Explain how gas inside a container exerts pressure on the container.

  The particles of a gases are moving randomly and collide with the walls of the container. This exerts a pressure on the container wall.
• What are the units of pressure?

  Pascals (Pa)
• What is the formula that links area, force and pressure?

  Pressure = Force / Area
• What is the relationship between pressure and volume of a gas (assuming temperature is kept constant)

  When kept at the same constant temperature, the pressure and volume of a gas are inversely proportional. This means that as one increases, the other decreases.

  For example, if you decrease the volume of a container, then the pressure will increase.
• What are the units of pressure in a liquid?

  Pascals (pa)
• What is perpendicular force?

  component of the force which is at a right angle to the surface its colliding with.
• The term 'fluid' can refer to either a liquid or a gas.

  Fluids exert pressure on their containers.

  The liquid or gas particles collide with the walls of the container. These collisions exert a force onto the walls of the container, and this force is pressure.
• Which factors can increase the pressure of a gas?

  1. More collisions with the walls of the container.
  2. Faster moving particles.
• How does temperature and concentration affect a flexible container?

  1. Some containers, such as balloons, are flexible
  2. An increase in force on the walls of the container would just cause the container to expand.
  3. Therefore, changing temperature or concentration will change the volume of the container, rather than the pressure of the gases inside.
• Increasing temperature increases pressure (in a fixed volume container) Increasing temperature increases volume (in a flexible container) Increasing concentration increases pressure (in a fixed volume container)
• For a gas at constant temperature, pressure x volume always equals the same constant. Therefore:

  p1V1=p2V2

  Where:

  p1 is the initial pressure

  V1 is the initial volume

  p2 is the pressure after a change occurs

  V2 is the volume after a change occurs