chemical changes
changes to the chemical structure of a substance (when the changes are reversed, the substance doesn’t usually revert back to its original structure)
condensation
the changing from a gas to liquid (cooling of gas)
Density
the mass per unit volume of an object
evaporation
the changing from a liquid to a gas (heating of liquid)
freezing
the changing from a liquid to a solid (cooling of liquid)
gas temperature relationship with kinetic energy
it 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
kinetic energy + all potential energies of particles = internal energy
latent heat
the energy required for a substance to change state
melting
the changing from solid to liquid (heating of solid)
pascals
unit of pressure (equal to a force of one N acting perpendicular to an area of 1m^2)
physical changes
changes to the physical properties of a substance which can be reverse
pressure
force acting perpendicular to a surface, per unit area
specific heat capacity
amount of energy needed to increase the temperature of 1kg of a given substance by 1 degree
specific latent heat of fusion
amount of energy needed to change the state of 1kg of a substance from solid to liquid maintaining same temperature
specific latent heat of vaporisation
amount of energy needed to change the state of 1kg of a substance from liquid to gas maintaining the same temperature
specific latent heat
amount of energy needed to change the state of 1kg of a substance maintaining the same temperature
sublimination
direct changing of a substance from solid to gas without passing through the liquid phase