Physics 3: Particle Model of Matter

Section 1: Key Terms Section 4: Heating and Cooling Curves State of matter The form which a substance can take (e.g. solid, liquid, gas) Heating Curve Density A substance’s mass per unit volume Melt Change of state from solid to liquid Freeze Change of state from liquid to solid Boil Change of state from liquid to gas Evaporate Change of state from liquid to gas Condense Change of state from gas to liquid Sublimate Change of state from solid to gas without passing through the liquid state. Cooling Curve Physical A change in which a material recovers its original properties if Change the change is reversed Internal Energy The total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system. Heating Process which changes the energy stored within a system by increasing the energy if the particles which make up the system. This either raises the temperature or causes a change of state. Specific Heat The amount of energy required to raise the temperature of one Capacity kilogram of the substance by one degree Celsius. Section 5: Gas Behaviour Specific Latent The energy required to change the state of one kilogram of the The temperature of a gas is related to the Heat substance with no change in temperature. average kinetic energy of the molecules. Specific Latent Change of state from solid to liquid Changing the temperature of a gas with a Heat of Fusion fixed volume changes the pressure exerted by Specific Latent Change of state from liquid to vapour the gas. Heat of Increasing the volume of a gas with fixed Vaporisation temperature reduces the pressure. Work The transfer of energy by a force. Doing work on a gas increases the internal energy of the gas and can cause an increase in the temperature of the gas. Section 2: Equations to Learn Equation Symbol Equation Units Density = mass ÷ volume Ρ = m ÷ V Density (ρ) – kilograms per meters cubed (kg/m3) Mass (m) – kilograms (kg) Volume (V) – meters cubed (m3) Change in thermal energy = mass × ΔE = mcΔθ Change in internal Energy (ΔE) – Joules (J) specific heat capacity ×temperature Mass (m) – kilograms (kg) change Specific heat capacity (c) – joules per kilogram per degree Celsius (J/kg/ᵒC) Temperature change (Δθ) – degrees Celsius (ᵒC) Energy for a change of state = mass × E = mL Energy – Joules (J) specific latent heat Mass (m) – Kilograms (kg) Specific latent heat (L) – joules per kilogram (J/kg) Pressure × volume = constant (for a pV = constant Pressure (p) – Pascals (Pa) fixed mass of gas at constant Volume (V) – metres cubed (m3) temperature) Section 3: States of Matter State Particle Arrangement Particle Motion Relative Diagram Energy Density Solid Strong forces of attraction hold particles Particles can vibrate about their fixed High close together in a fixed, regular positions. arrangement.

Liquid Weaker forces of attraction between Particles can move past each other in Medium particles. Particles are close together but random directions at low speeds. irregularly arranged.

Gas Almost no forces of attraction between Particles free to move and travel in Low particles. random directions at high speed.