When a substance changes state, mass is conserved.
A solid changing to a gas is called subliming.
When a gas turns into a liquid, it is called condensation.
Changes of state are physical changes that differ from chemical changes because the material recovers its original properties if the change is reversed.
Internal energy is energy stored inside a system by particles (atoms and molecules) that make up the system.
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.
to calculate the change in thermal energy, use ∆E=mc∆θ
The specific heatcapacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.
The specific latentheat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature.
When a change of state occurs, the energy supplied changes the energy stored (internal energy) but not the temperature.
to calculate the energy needed for a change of state, use E=mL
The molecules of a gas are in constantrandommotion
The temperature of the gas is related to the average kinetic energy of the molecules.
Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas.