Matter

• What type of change are changes of state and why?

  Physical changes

  No new substances are produced

  Mass stays the same because the number of particles doesn't change
• Density equation

  Density = Mass/Volume
• Solid Arrangement, Movement, Properties (DVS)

  Arrangement: Particles held next to each other in fixed positions by strong forces of attraction

  Movement: Vibrate about fixed positions

  Properties: High density, fixed volume, fixed shape
• Liquid Arrangement, Movement, Properties (DVS)

  Arrangement: Particles are in contact with each other, weaker force of attraction than solids

  Movement: Free to move randomly

  Properties: Lower density than solids, Fixed volume, Not fixed shape
• Gas Arrangement, Movement, Properties (DVS)

  Arrangement: Particles spread out, almost no forces of attraction

  Movement: Move randomly at high speed

  Properties: Low density, No fixed volume, Not fixed shape
• Internal energy

  Increases when a substance is heated

  The sum of the total kinetic energy and the total potential energy
• Latent heat: Energy transferred when a substance changes shape
• Specific latent heat: The energy required to change 1kg of substance with no change in temperature
• Specific latent heat of fusion: The energy required to melt 1kg of substance with no change in temperature
• Specific latent heat of vaporisation: The energy required to evaporate 1kg of substance with no change in temperature
• Specific heat capacity: The amount of energy needed to raise the temperature of 1kg by 1 degree
• When a substance is heated or cooled the temperature change depends on:

  Substances mass

  Type of material

  How much energy is transferred to it
• Gas temperature

  Related to the average kinetic energy of its particles
• Gas pressure

  The pressure a gas exerts on a surface is caused by the force of the gas particles hitting the surface
• Why does the pressure of a gas in a sealed container increase when the the temperature is increased?

  1. The particles move faster so hit surfaces with more force
  2. Number of impacts per second increases, exerting more force overall
• Why can the temperature increase when a gas is compressed quickly?

  Energy gained by the gas is not transferred quickly enough to its surroundings
• What happens if the kinetic store of a substance increases or decreases enough?

  It may change shape