(acids and alkalis)

• indicators in acid:

  litmus paper - red

  methl orange - red

  phenophthalein - colourless

  universal indicator - red/orange
• indicators in alkalis:

  litmus paper - blue

  methyl orange - orange

  phenothphalein - pink

  universal indicator - blue/purple
• acid + metal -> salt + hydrogen
• acid + carbonate -> salt + CO2
• acid + metal oxide -> salt + water
• acid + alkali -> salt + water
• metal + acid method:

  1. 1 piece of magnesium to 5cm hydrochloric acid
  2. hold finger over test tube
  3. light splint (flame go out with squeaky pop)

  (fizzing, warm tube, squeaky tube)
• metal oxide + acid method:

  1. 1/2 spatula of copper oxide to 10 cm dilute sulfuric acid
  2. warm beaker in hot water

  (colourless -> blue colour change)
• metal carbonate + acid method:

  1. 1/2 spatula of copper carbonate to 10 cm dilute hydrochloric acid

  (green -> turquoise/blue ocolour change, fizzing, warm tube)
• metal hydroxide + acid method:

  1. 5 cm dilute sodium hydroxide to 5 cm dilute hydrochloric acid
  2. thermometer to record temperature change

  (increased temperature)
• crystallisation of soluable salt method:

  1. measuring cylinder to add 25cm sulfuric acid
  2. 1/2 spatula of copper carbonate, stir
  3. add until excess
  4. filter solution, pour filtrate in evaporating dish
  5. evaporating dish on beaker with hot water, heat with bunse burner
  6. stop heating + sit to crystallise

  (fizzing when copper carbonate mixed with sulfuric acid, small crystals during heating)
• soluable salts:

  • group 1 + ammonium compounds
  • nitrate compounds
  • common chlorides (except silver + lead (II))
  • common sulfates (except barium, calcium, lead (II))

  (e.g. calcium chloride, silver nitrate, copper sulfate)
• insoluable salts:

  • common carbonates (except group 1 and ammonium)
  • common hydroxides (except group 1 and calcium)

  (e.g. copper carbonate, lead sulfate, magnesium hydroxide)
• precipitation reactions method:

  1. 10 test tubes
  2. 1 cm of lead nitrate + 1 cm of potassium iodide (mix)

  lead nitrate + potassium iodide -> lead iodide (yellow)

  lead nitrate + sodium sulfate -> lead sulfate (milky white)

  barium chloride + sodium sulfate -> barium sulfate (milky white)

  copper sulfate + sodium hydroxide -> copper hydroxide (blue)

  sodium chloride + silver nitrate -> silver chloride (milky white)
• oxygen test:

  • glowing splint in test tube (flame relit, went out again)
• carbon dioxide test:

  • pipette to add 1 cm limewater to gas, shake (turns cloudy)
• hyrogen test:

  • upside down test tube, lit splint in tube (flame went out with squeaky pop)
• chlorine test:

  • damp litmus paper (blue) in test tube with gas (paper turns red where dry)
• ammonia test:

  • damp litmus paper (red) in test tube with gas (paper turns blue where wet)
• water test:

  • add drops of distilled water to anhydrous copper sulfate (white powder turns blue)
• flame tests method:

  1. 1 spatula of lithium chloride to watch glass + drops of distilled water
  2. clean wire by moving it between acid and flame
  3. dip wire in acid, hold it in flame
  4. repeat with different acids for different coloured flames
• flame test results:

  • lithium chloride (red)
  • sodium chloride (yellow)
  • potassium chloride (lilac)
  • calcium chloride (orange)
  • copper chloride (green)
• testing for metal ions method:

  1. 3 test tubes with 1 cm metal solution
  2. few drops of sodium hydroxide
  3. repeat for other solutions
• testing for metal ions results:

  • Cu (bright blue -> darker blue, solid)
  • Fe (II) (muddy brown -> green)
  • Fe (III) (yellow -> orange/brown)
• test for ammonium ions method:

  1. 1 spatula of ammonium sulfate in boiling tube
  2. add 1-2 cm solution hydroxide
  3. heat gently for 15 seconds
  4. damp universal indicator inside test tue

  (paper turns blue)
• cations are poositively charged ions that form when an atom loses one or more electrons during a reaction
• anions are negatively charged ions that form when an atoms gains one or more electrons during a reaction
• test for halide ions method:

  1. 5 test tubes in a rack, fill with 5 salt solutions
  2. add drops of nitric acid, and then drops of silver nitrate
  3. shake and note down name of precipitate
  4. repeat with others

  chloride = white precipitate

  bromide = cream precipitate

  iodide = yellow precipitate
• a salt solution that contains sulfate ions can be tested with acidified barium chloride (produces white precipitate)
• a salt solution containing carbonate ions can be tested with hydrochloric acid (limewater turns milky)
• a salt solutions can be tested for halide ions with acidified silver nitrate