Science

• Mixture

  A combination of two or more substances in which each retains its own chemical properties (e.g. tea and blood)
• Compound


  A substance formed by the chemical combination of two or more elements, with distinct properties different from the individual elements (e.g. water, carbon dioxide)
• Element

  The fundamental substances that cannot be broken down into simpler substances by chemical means (e.g. carbon)
• States of matter


  • Solid
  • Liquid
  • Gas
• Solids

  • Particles are closely packed, held by strong forces, vibrate in fixed positions
• Liquids

  • Particles are slightly farther apart, forces of attraction are weaker, particles move more randomly
• Gases

  • Particles are far apart, forces of attraction are weak, particles move freely
• Volume

  The amount of space occupied by matter
• Solids

  • Have definite volume (volume doesn't change)
• Liquids

  • Do not have definite volume
• Shape

  The form of an object or its outline
• Solids

  • Have a definite shape
• Liquids and Gases

  • Do not have definite shape
• Density

  The mass of a substance per unit volume
• Density varies from one substance to another and depends on the type of particles that make up the matter and how they are arranged
• Density is affected by changes in temperature
• Compressibility

  The change in volume of matter when external pressure is applied
• Solids

  • Are incompressible because their particles are tightly packed together
• Liquids

  • Are different to compress because the spaces between their particles are small
• Gases

  • Are compressible because the spaces between their particles are large
• Flow

  To continuously stream or move
• Solids

  • Do not have flow because their particles are tightly held by strong forces of attraction
• Liquids and Gases

  • Flow because their particles have spaces between them and are not tightly bound to each other
• Properties of matter in different states

  • Volume
  • Shape
  • Compressibility
  • Ability to Flow
• Strand

  • Mixtures, compound & elements
• Diffusion of Liquids

  1. Scoop potassium manganate (VII) crystals into a straw

  2. Dip the straw into water in a beaker

  3. Let the potassium manganate crystals move down the straw to the bottom of the beaker

  4. Carefully withdraw the straw
• Diffusion

  The movement of particles from a region where they are more concentrated to a region where they are less concentrated
• Strand

  • Mixture, compound, elements, substances
• Physical change

  A temporary change that occurs without the formation of a new substance
• Physical change

  • The change is reversible
  • No new substance is formed
  • There is no change in mass
  • No heat is gained or lost
• Chemical change

  A temporary change where new products are formed but the change is reversible
• Chemical change

  • The change is reversible
  • New substances are formed
  • There is a change in mass
  • It is accompanied by a change in heat
• Heating hydrated copper (II) sulphate and hydrated cobalt (II) chloride

  1. Measure and record the mass of the boiling tubes

  2. Put the hydrated crystals into the boiling tubes

  3. Heat the tubes gently until there is no further change in colour

  4. Allow the tubes and contents to cool

  5. Measure and record the new mass
• Heating hydrated copper (II) sulphate forms anhydrous copper (II) sulphate and water
• Heating hydrated cobalt (II) chloride forms anhydrous cobalt (II) chloride and water
• Water of crystallisation

  The water that forms part of the crystal structure of a salt
• Hydrated

  Containing water
• Anhydrous

  Lacking water
• Heating copper (II) nitrate

  1. Measure and record the mass of the boiling tube

  2. Add copper (II) nitrate crystals to the tube

  3. Measure and record the new mass

  4. Gently heat the copper (II) nitrate

  5. Allow the tube and contents to cool

  6. Measure and record the new mass
• Permanent change

  An irreversible change where one or more new substances are formed, accompanied by a change in mass and heat