Particle model of matter

• Density is the amount of mass within each metre cubed of a material
• Density = Mass/Volume; D = m/V
• Higher density materials have particels packed closer together than those with a lower density
• The 3 states of matter are solid, liquid and gas
• Particles in a material have both potential and kinetic energy
• Internal energy is the total sum of all the kinetic and potential energy of the particles in the material 
• Heating a material transfers energy to particles causing either a change of temperature or a change of state
• The amount of/rate of change in temperature depends on the material type, the mass and amount of energy input
• Heating or cooling of a substance can lead to a change of state
• A change of state is a physical change in which mass in conserved
• Energy transferred during a change of state is being used to break or form bonds rather than change its temperature
• Graphs have horizontal (flat) sections which indicate a change of state is occuring, so energy is not causing change in temp
• Specific Latent Heat is the amount of energy needed to change the state of a substance
• SLH is the amount of energy required to change 1kg of a substance from one state to another at a constant temperature
• SLH of fusion is for changes bewteen solids and liquids;


  SLH of vaporisation is for changes between liquids and gases
• Specific Latent Heat = Energy required to change state/mass of material changing state


  (L = E/m)
• SHC = energy/(mass x temperature change);

• The amount of energy required to raise the temperature of an object depends on the material it is made from
• Specific Heat Capacity (SHC) is the amount of energy required to raise the temperature by 1oC if there is 1kg of a material
• Electrical energy = current x voltage x time;
• Particles in a gas are constantly moving with random directions and speeds
• Increasing the temperature of a gas increases the average kinetic energy (and speed) of the particles
• Particles collidng with the walls of a container will exert a force, hence pressure, on the container
• An increase of temperature for a gas of constant volume will increase pressure
• An decrease of volume of a gas at constant temperature will increase pressure
• A change in pressure can cause a change in the volume of a gas if it is not in a fixed container 
• Doing work on a gas can increase its presuure and temperature 
• Pressure x Volume = Constant (for a gas at constant temperature): PV = constant