Chemistry

• States of matter


  Solid, liquid, gas
• Solid


  • Orderly arranged particles with less kinetic energy
  • Particles held in a fixed lattice
  • Constant amount of space and does not change shape
• Liquid


  • Particles have more kinetic energy than solids
  • Particles not held in a fixed lattice
  • Constant amount of space but can change shape to fit container
• Gas


  • Particles have the most kinetic energy
  • Particles move randomly with no fixed arrangement
  • No definite shape or volume
• Brownian motion was observed by botanist Robert Brown in 1827
• Brownian motion led to the conclusion that matter is made up of tiny particles
• Diffusion


  Movement of particles from high concentration to low concentration
• Kinetic molecular theory


  Theory that attempts to explain the behavior of matter in different phases
• Principles of kinetic molecular theory

  • Matter consists of small particles
  • Particles are in constant motion
  • There are spaces between the particles
  • There are forces of attraction between the particles
  • Particles collide with the sides of the container and each other
• Increase in particle energy

  Weakens or overcomes intermolecular forces, resulting in a change of state
• In a liquid and gas at the same temperature, the average kinetic energy of the particles is equal
• Practical Activity


  1. Add a crystal of potassium permanganate or a drop of food colouring to water

  2. Observation: The colour slowly spreads out through the water
• Diffusion


  The movement of atoms or molecules from an area of higher concentration to an area of lower concentration
• • High Concentration
  • Low Concentration
• Matter can change between states when the temperature is increased or decreased
• Solid to Liquid


  Intermolecular forces weakened
• Liquid to Gas

  Intermolecular forces overcome
• Sublimation

  The process during which a solid changes directly into a gas without passing through an intermediate liquid
• Melting

  The process during which a solid changes to a liquid by the application of heat
• Evaporation

  The change of a liquid into a vapour at any temperature below the boiling point
• Condensation


  The process during which a gas or vapour change into a liquid either by cooling or by being subjected to increased pressure
• Freezing

  The process during which a liquid changes to a solid by the removal of heat
• Freezing point

  The temperature at which a liquid changes to a solid by the removal of heat
• Melting point

  The temperature at which a solid, given sufficient heat, becomes a liquid
• Boiling point

  The temperature of a liquid at which its vapour pressure equals external atmospheric pressure
• If a liquid is heated then bubbles of gas appear inside the liquid and this is known as boiling
• In 1828 Robert Brown observed that pollen grains suspended in water moved about in a rapid, irregular (jerky) motion
• Brownian motion

  The random movement of microscopic particles suspended in a liquid or gas, caused by collisions between these particles and the molecules of the liquid or gas
• In grade 8 you would have observed Brownian motion using a SMOKE CELL
• Practical Activity


  1. Add a crystal of potasium permanganate or a drop of food colouring to water

  2. Observation: The colour slowly spreads out through the water
• Diffusion


  The movement of atoms or molecules from an area of higher concentration to an area of lower concentration
• Matter can change between states when the temperature is increased or decreased
• As we heat an object


  It goes from a solid to a liquid (intermolecular forces weakened) to a gas (intermolecular forces overcome)
• As we cool an object


  It goes from a gas to a liquid to a solid
• Sublimation


  The process during which a solid changes directly into a gas without passing through an intermediate liquid state
• Melting


  The process during which a solid changes to a liquid by the application of heat
• Evaporation


  The change of a liquid into a vapour at any temperature below the boiling point
• Condensation

  The process during which a gas or vapour changes into a liquid either by cooling or by being subjected to increased pressure
• Freezing


  The process during which a liquid changes to a solid by the removal of heat
• Freezing point


  The temperature at which a liquid changes to a solid by the removal of heat