CHEMISTRY

• Testing hydrogen

  1. Collect gas in test tube

  2. Lit splint

  3. Squeaky pop sound
• Testing oxygen

  1. Take a lit splint

  2. Blow out the flame

  3. Put glowing splint in tube, reignites
• Testing carbon dioxide

  1. Bubble gas through limewater

  2. Colourless to cloudy
• Testing chlorine

  1. Damp litmus paper in test tube

  2. Blue to white (bleached)
• Testing ammonia

  Turns red litmus paper blue
• Flame tests

  1. Dip inoculating loop in hydrochloric acid, then put in flame

  2. Dip loop in hydrochloric acid then solid compound, dip in flame
• Metal ion flame test colours

  • Lithium, Li - Red
  • Sodium, Na - Yellow
  • Potassium, K - Lilac
  • Calcium, Ca - Orange-red
  • Copper, Cu - Blue-green
• Metal ions

  • Aluminium, Al 3+ - Green precipitate
  • Calcium, Ca - White precipitate
  • Copper, Cu - Blue precipitate
  • Iron II, Fe 2+ - Sludgy green precipitate
  • Iron III, Fe 3+ - Brown precipitate
• Testing cations

  1. Dissolve solid compound

  2. Add sodium hydroxide solution
• Ammonia ions (NH4+) react with hydroxide ions (OH-) to produce ammonia gas (NH3) and water
• Testing anions - carbonates


  1. Add dilute hydrochloric acid to ionic compound

  2. Bubble gas through limewater, colourless to cloudy
• Testing anions - halides

  1. Dissolve solid compound in deionised water

  2. Add dilute nitric acid

  3. Add silver nitrate solution
• Halide ion precipitates

  • Chloride, Cl - White
  • Bromide, Br - Cream
  • Iodide, I - Yellow
• Testing anions - sulfates

  1. Dissolve small ionic compound in deionised water

  2. Add hydrochloric acid then barium chloride
• Ionic bonding


  When a metal reacts with a non-metal, this is called ionic bonding
• Group I metals

  • Lose 1 electron forming 1+ ion
  • Group 7 non-metals gain one electron forming 1- ion
• Ionic compounds

  • Have very high melting and boiling points
  • Cannot conduct electricity when solid as the ions cannot move
  • Can conduct electricity when molten/aqueous as the ions can move and carry charge
• Ionic compounds can only conduct electricity when liquid because the ions are free to move and carry charge
• Ionic compounds

  • Have high melting and boiling points because ionic bonds are very strong, and a high amount of energy is required to break the bonds
• Ion

  An electrically charged atom or group of atoms formed by loss or gain of electrons
• Types of ions

  • Negative ions have more electrons than protons
  • Positive ions have more protons than electrons
• Insoluble

  Solid that won't dissolve in water
• Soluble


  Solid that will dissolve in water
• Aqueous

  Dissolved in water
• Molten

  Liquid state
• Group 1 physical properties

  • Soft, malleable
  • Low melting points when going down the group
  • Produce metal hydroxides and hydrogen when reacting with water
  • Solids, conductors
  • Low density, decreases as you go down the group
• Group 1 elements are very reactive and must be stored under oil to keep air and water away from them
• Reactions of Group 1 elements with water

  1. Form metal hydroxides which are alkaline (pH over 7)

  2. Reactivity increases going down the group as atoms get larger and outer electron is more easily lost
• The reactivity of Group 1 elements increases as the atoms get larger and the outer electron is further from the nucleus, so the electrostatic attraction is weaker and the electron is more easily lost
• Ionic lattice


  • Ions are arranged in a regular repeating lattice
  • Held together by strong electrostatic forces between oppositely charged ions
  • Brittle, if twisted or distorted the structure breaks