Density = Mass/Volume
kg/m3 kg m3
Mass is conserved, even when a substance changes state
Changes of state are physical changes which differ from chemical changes because the material recovers its original properties if the change is reversed
Energy is stored inside a system by the particles (atoms and molecules) that make up the system. This is called internal energy.
Internal energy is the total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system.
Heating changes the energy stored within the system by increasing the energy of the particles that make up the system. This either raises the temperature of the system or produces a change of state.
If the temperature of the system increases, the increase in temperature depends on the mass of the substance heated, the type of material and the energy input to the system.