Chemistry topic 3

• What is ionic equation for neutralization

  H+ + Cl- is H20
• What are the common acids

  Hydrochloric acid (HCl)

  Sulphuric acid (H2SO4)

  Nitric acid (HNO3)
• What are common alkalis

  Sodium hydroxide (NaOH)

  Lithium hydroxide (LiOH)

  Magnesium hydroxide(Mg(OH2)
• What is concentrated

  Lots of particles
• What is dillute

  Few particles
• Strong acids

  Fully dissociate/ionise into H+ and Cl-
• Weak acids 


  Do not fully dissociate in water

  Not all H+ given to acid strength
• How can stong acid be made less acidic

  By adding water(dilluting it)
• How can strong alkaline be less alkali

  Adding more water dilluting it
• Strong acid can be placed in 20cm or 50cmcubed

  In 20cm it's

  In 50 cm its

  -more concentrated

  -more dilluted
• What substances aren't soluble s_ l_ b_ cc _ h_

  Silver

  Lead

  Barium

  Common carbonates

  Hydroxides
• Which substances are soluble An_ Cc_ Cs_ S_ P_ A_

  All nitrates

  Common chloride

  Co mon sulphates

  Sodium

  Potassium

  ammonium
• Base + acid -> salt + water
• Metal + acid -> salt + hydrogen
• Metal carbonate + acid -> salt + water + carbon dioxide
• Test for hydrogen gas:

  1. Get a lit splint
  2. Burns with a squeaky pop when hydrogen is present
• Test for carbon dioxide:

  1. Bubble through limewater
  2. Goes cloudy
• Acids are sources of hydrogen ions

  Alkali in solution are sources of hydroxide ions
• Litmus

  • Acidic - red
  • Alkaline - blue
• Phenolphthalein

  • Acidic - colorless
  • Alkaline- pink
• Methyl orange

  • Acidic - red
  • Alkaline - yellow
• The higher the concentration of hydrogen ions in solution the lower the pH. The higher the concentration of hydroxide in an alkaline solution the higher the pH
• As hydrogen ions concentration in a solution increases by 10 pH decreases by 1
• Alkalis are soluble bases that can neutralise acids to form water and a salt
• Ionic equation for neutralization 


  H+ + OH- -> H20
• A neutralization reaction is reaction between acid and base
• Acid-alkali neutralization as a reaction in whiwhich hydrogen ions reaction with hydroxide ions from alkali to form water
• Strong acid can be made less acidic by dilluting it with water.
• Preparing soluble salts from acid and insoluble reactant

  1. Add all insoluble solid to acid until no more reacts(you need to add excess to makd sure all acid reacts, you should see unreacted solid at bottom)
  2. Filter solution to remove excess solid(remaining solution must be salt and water)
  3. Use crystallization to get sample of salt
• Titration is used to prepare a soluble salt from acid and soluble reactant(alkali)

  1. Titration finds right amount of alkali
  2. Then measure alkali amount out again and add to acid
  3. Now solution at end is just salt and water
  4. Use crystallization to get pure dry sample of salt
• How to get pure, dry sample of insoluble salt

  1. Mix similar volumes of 2 solutions that will form precipitate toghether
  2. Filter out precipitate
  3. Rinse precipitate with distilled water(makes sure samples pure)while still in funnell
  4. Leave sample to dry on filter paper
• Titration is when you make Salt from acid and alkali
• 1. Using pipette transfer known volume of alkali into conical flask
  2. Add drops of indicator usually phenolphthalein
• 3.add acid from burette slowly until you are near to indicator changing colour

  4.keep adding acid until indicator changes colour

  5. Record volume of acid
• Ionic equation

  2H+ + 2e -> H2
• As hydrogen ions concentration in a solution increases by 10 what does pH decrease by?

  pH decreases by 1