Chemistry

• Atom


  Substance made up of
• Physical states


  • Solid
  • Liquid
  • Gas
• Particles in a solid

  • Packed tightly together
• Particles in a liquid


  • Still touching, can move
• Particles in a gas

  • Random, far apart
• Element


  One type of atom present
• Compound


  2 or more types of atom chemically bonded in the same way
• Mixture


  A combination of two or more types of atoms that are chemically bonded in different ways or not at all
• Element


  • A bar of gold
• Compound


  • Carbon dioxide (CO2)
• Mixture


  • Cement (sand, water, gravel)
• Soluble


  Capable of being dissolved
• Insoluble


  Incapable of being dissolved
• Solution


  A mixture that solute(s) dissolving in solvent
• Solute


  A substance that is dissolved in a solvent
• Solvent


  A liquid substance capable of dissolving other substances
• Diffusion


  Moving from an area of high concentration to an area of low concentration
• Diffusion in a liquid takes slower
• Pure substance


  A single substance made of only one type of particle
• Impure substance


  A substance with more than one kind of element or compound
• Chromatography


  It separates substances with a mixture bases on their physical properties
• Acid/alkali colours


  • Acid: red
  • Alkali: blue/purple
  • Strong alkali: dark blue/purple
  • Strong acid: dark red
  • Neutral pH: green
• Properties of metals


  • Electrical and thermal conductors, high melting and boiling points
• Properties of non-metals


  • Dull, low melting points, poor conductors of electricity and heat
• Boiling point


  The temperature at which a liquid changes to a gas
• Melting point


  The temperature at which a solid becomes a liquid
• Universal indicators tell us the pH of a substance
• Element


  An atom that consists of only one type of atom. It cannot be broken down into simpler substances by chemical means.
• Compound


  A substance made up of two or more different elements that are chemically bonded together in a fixed ratio.
• Mixture


  A combination of two or more substances that are not chemically bonded together.
• Main changes of state?

  • Melting
  • Evaporating
  • Condensing
  • Freezing
• Pure substance


  Contains only one type of molecule or atom
• Impure substance


  Contains more than one type of molecule or atom