Matter

• When there is an increase in temperature


  the molecules will increase in movement speed
• The higher the mass of the particle, the slower its movement or rate of diffusion
• Definition of diffusion

  Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration until the particles are evenly distributed.
• Diffusion in gases (eg. air and bromine gas)

  The air particles have diffused downwards to the bottom of the glass jar, while the bromine particles have diffused upwards to the top of the jar until both gases have mixed completely and all the particles have been evenly distributed.
• Diffusion in liquids (eg. water and copper)

  The water particles have diffused to a region with a lower concentration of water while the copper and sulfate particles have diffused in a region of lower concentration of those particles until all particles are evenly distributed throughout the container.
• When the temperature of a liquid or gas increases, the rate of diffusion also increases.
• At a higher temperature, the particles gain more kinetic energy. 


  Thus they will move around at a higher speed from a region of higher concentration to a region of lower concentration until they are evenly distributed.
• SOLID (properties)

  Fixed shape; particles occupy fixed positions
• SOLIDS (properties)

  Fixed volume / cannot be compressed; very little empty space in between particles
• LIQUID (properties)

  No fixed shape; particles do not occupy fixed positions
• LIQUIDS (properties)

  Fixed volume / cannot be compressed; little empty space in between particles
• GAS (properties)

  No fixed shape; particles do not occupy fixed positions
• GAS (properties)

  No fixed volume / can be compressed easily; a lot of empty space in between particles
• SOLID (arrangement)

  Very closely packed in an orderly manner
• LIQUID (arrangement)

  Closely packed in a disorderly manner
• GAS (arrangement)

  Very far apart in a disorderly manner
• SOLID (movement or particles)

  Vibrate and rotate about in fixed positions
• LIQUID (movement of particles)

  Slide and roll past one another freely throughout the liquid
• GAS (movement of particles)

  Move quickly and randomly in any direction
• SOLID (forces of attraction between particles)

  Very strong, enough to keep particles closely packed and in fixed positions
• LIQUID (forces of attraction between particles)

  Less strong, enough to keep particles close together but allow them to roll and slide randomly
• GAS (forces of attraction between particles)

  Very weak, negligible
• Solid to Gas

  Sublimation / Sublime
• Gas to Solid

  Deposition / Deposits
• Pure solids will melt at a sharp temperature
• Pure liquids will boil at a sharp temperature
• Effects of impurities on melting point

  Causes melting point to be lower than that of the pure substance; the solid will melt over a temperature range
• Effects of impurities on boiling point

  Causes boiling point to be higher than that of the pure substance; the liquid will boil over a temperature range.
• Why is the solid changing state? (eg. when melting or boiling)

  This is because the particles gain heat energy which is used to weaken the attractive forces between particles. Thus the particles can now move further away from one another.
• Why does the temperature remain constant during a change of state?(melting or boiling)

  The particles do not gain kinetic energy, thus the temperature remains constant.
• Why does the temperature remain constant when cooling down and changing state? (condensation or freezing)

  It is because, during the process of condensation, heat energy is released as the particles are attracted to each other, thus forming a liquid. There is no change in kinetic energy, therefore the temperature remains unchanged.
• Gases can be compressed easily as the particles are far apart and there are a lot of empty spaces between particles. Thus when the pressure is increased, the gas particles are pushed closer to each other and therefore the volume occupied by the gas decreases
• Solids cannot be compressed as the particles are very close to each other and there is very little space between particles. Thus, when pressure is increased, the particles cannot be pushed closer to each other and therefore there is no change in volume
• A small volume of water produces a much greater volume of steam.

  In water, there is very little space between particles hence there are a lot of water particles in a small volume. Thus, more water particles will become steam particles, producing a much larger volume of steam.