pmt definitions

• Change in Thermal Energy


  The product of the mass, specific heat capacity and temperature change of a substance
• Chemical Changes

  Changes to the chemical structure of a substance. The substance does not usually restore its original properties when the changes are reversed
• Condensation


  The changing from vapour state to a liquid state, when a substance is cooled
• Density


  The mass per unit volume of an object
• Evaporation


  The changing from liquid state to a vapour state, when a substance is heated
• Freezing


  The changing from a liquid state to a solid state, when a substance is cooled
• Gas Temperature

  The temperature of a gas is directly proportional to the average kinetic energy of its molecules
• Internal Energy

  The energy stored by the atoms and molecules that make up a system. It is equal to the sum of the total kinetic and potential energies of the particles in the system
• Latent Heat

  The energy required for a substance to change state
• Melting


  The changing from solid state to liquid state, when a substance is heated
• Pascals


  The unit of pressure, equal to a force of one Newton acting perpendicular to an area of one metre squared
• Physical Changes

  Changes to the physical properties of a substance which can be reversed. Changes of state are physical changes since substances can restore their original properties when the changes are reversed
• Pressure


  The force acting perpendicular to a surface, per unit area
• Specific Heat Capacity

  The amount of energy needed to increase the temperature of one kilogram of a given substance by one degree Celsius
• Specific Latent Heat of Fusion


  The amount of energy needed to change the state of one kilogram of a substance from solid state to liquid state, whilst held at constant temperature
• Specific Latent Heat of Vaporisation

  The amount of energy needed to change the state of one kilogram of a substance from liquid state to vapour state, whilst held at constant temperature
• Specific Latent Heat


  The amount of energy needed to change the state of one kilogram of a substance, whilst held at constant temperature
• Sublimation


  The direct changing of a substance from a solid state to a vapour state, without passing through the liquid phase