Particle Model of matter AQA

• solids

  -particles very close together

  -arranged in regular pattern

  -vibrate in fixed position

  
• liquids

  -particles very close together

  -not arranged in regular pattern

  -particles can move around each other

  
• gases

  -particles very far apart

  -not arranged in any pattern

  -particles moving very rapidly

  
• density

  the density of a material tells us the mass for a given volume
• density formula

  density (kg/m³) = mass (kg) / volume (m³)
• energy in particles

  -kinetic when moving

  -potential = intermolecular bonds + chemical bonds
• internal energy

  -energy stored in a system by particles

  -total kinetic energy + potential energy of all the particles that make up the system
• sublimation

  -solid turning directly into a gas
• when changes of state take place...

  mass is always conserved
• changes of state are...

  physical changes, if we reverse the change: material recovers its original properties
• specific heat capacity

  amount of energy required to raise the temperature of 1kg of the substance by 1°C
• specific heat capacity formula

  change in thermal energy (j) = mass (kg) x specific heat capacity (j/kg) x change in temperature (°C)
• Describe and explain a heating curve.

  -temp of solid rising as we increase kinetic energy of particles

  -at some point temp stop increasing + line becomes horizontal.

  -internal energy and potential energy increases

  -at this point solid turning to a liquid (melting) because energy is weakening/breaking forces of attraction between particles

  -temp rises again

  -line flattens/becomes horizontal again, boiling at this point and turns to gas

  
• during the changing of state...

  potential energy increases, kinetic energy stays the same. Temperature does not increase.
• specific latent heat

  amount of energy required to change the state of 1kg of the substance with no change in temperature
• specific latent heat of fusion

  amount of energy required to change 1kg of a substance from a solid to a liquid with no change in temperature
• specific latent heat of vaporisation

  amount of energy required to change 1kg of a substance from a liquid to a gas with no change in temperature
• Solid

  The state of matter where the particles are linked by strong forces. They are packed closely together and move very little. The particles usually form a regular and specific pattern.
• Liquid

  The state of matter where the particles have weaker bonds. They are still tightly packed but may move around each other.
• Gas


  The state of matter where particles are far apart and are in constant random motion. There is no interactive between the particles.
• Melting Point


  The temperature at which a solid turns into a liquid .
• Boiling Point


  The temperature at which a liquid turns into a gas.
• Melting


  When a solid changes to a liquid.
• Boiling


  When a liquid changes a gas at the boiling point
• Evaporating


  When a liquid changes to a gas below the boiling point
• Condensing


  When a gas changes to a liquid.
• Sublimating


  When a solid changes to a gas.
• Physical Change


  A change that does not produce a new substance. If the change is reversed the substance recovers its original properties.
• Internal Energy


  The total energy in the kinetic and potential stores of all the particles (atoms and molecules) that make up a system.
• Specific Heat Capacity

  The amount of energy required to raise the temperature of one kilogram of a substance by one degree Celsius. Often represented by the symbol 'c'. Its unit it J/kg°C.
• Kinetic Theory


  The theory that explains the different states of matter (solid, liquid and gas) by the arrangement and energies of their particles.
• Metres cubed (m³)

  The unit of volume.
• Density

  The mass per unit volume of a material. It can be thought of as representing how tightly packed the particles are within the material. Often represented by 'ρ'. The unit of density is kg/m³.
• kg/m³

  The standard unit of density.
• Kinetic Theory Of Matter

  Particle model of solids, liquids and gases which describes their properties.
• States Of Matter

  A form that substances take (e.g. solid, liquid and gas).
• Change Of State

  When a substance changes from one state of matter to another (e.g. a solid changing into a liquid).
• Degrees Celsius (°C)

  The unit of temperature and temperature change.
• Heating Curve

  A graph which shows how the temperature of a substance changes as it is heated.

  
• Cooling Curve

  A graph which shows how the temperature of a substance changes as it is cooled.