The particle model: solids are dense so particles are close together and vibrate about a fixed position. In liquids, particles are further apart and move around slowly within their volume. Gases are less dense so particles are far apart and move at random speeds in random directions.
Density = mass/ volume
Changes of state: melting, evaporating, condensing, freezing, sublimation (solid to liquid).
Physical changes differ from some chemical changes because the material recovers its original properties if the change is reversed.
Specific heat capacity: energy needed to increase the temperature of 1kg of a substance by 1oC.
Specific latent heat: energy needed to change the state of 1kg of a substance.
Q = mc∆T
c: specific heat capacity (given), T: temperature.
Q = mL
Q: energy needed (J), m: mass (kg), L: specific latent heat (given).
Conduction: heat energy passes through a solid as particles gain heat energy and then gain kinetic energy and then bump into each other and pass on heat energy.
Heat transfers can be reduced using cavity walls or double glazed windows. This is when you have two walls or two windows with a gap (vacuum) in between. This means that heat energy can't pass through by conduction because there is not one continuous solid.
Absolute zero: the particles have no thermal energy or kinetic energy, so they cannot exert a force (0 Kelvin = -2730C).
Celcius to Kelvin: add 273, and vice versa.
Gas exerts pressure at 90o to the walls of the container.
If you increase the volume of a gas, the pressure increases because there are more gas particles in the same volume.
Pressure = force/ area.
P1V1 = P2V2
Old pressure x old volume = new pressure x new volume because if one of them increases, the other decreases by the same factor.