Acids bases and salts (chem)

• Red and blue litmus paper will turn red with an acid, and with an alkali they will turn blue.
• Phenolphthalein with an acid is colourless and with an alkali turns pink.
• Methyl Orange will turn pink with acid and turn yellow with alkali.
• Strong acids are between 0-3 on the pH scale
• Strong alkalis are between 11-14 on the pH scale.
• In an aqueous solution acid releases hydrogen ions (H) and alkali release hydroxide ions (OH).
• An acid alkali titration:

  1. You fill a burette with acid.
  2. Then you fill a volumetric pipette with 25 cm cubed of soluble base and pour it into a conical flask.
  3. Add 2-3 drops of methyl orange to the conical flask.
  4. Next, add the acid into the conical flask whilst swirling it in order to mix it with the base.
  5. Do that until it turns orange and repeat until you get concordant results.
• Sodium, Potassium and ammonium compounds are soluble
• All nitrates are soluble
• Chlorides are soluble except Silver and Lead
• Sulphates are soluble except Barium, Calcium and Lead
• Carbonates are insoluble except Sodium, Potassium and Ammonium
• Hydroxides are insoluble except sodium, potassium and calcium
• Acids are proton donors and bases are proton acceptors.
• Acids release hydrogen ions which are made up of a single proton
• Alkalis release hydroxide ions which when they react with an acid it forms water.
• An alkali is a soluble base
• precipitation method:

  1. Add one of your solutions to a boiling tube.
  2. Add the same volume of the other solution to the same boiling tube
  3. Filter this mixture into a conical flask
  4. Finally add a small amount of distilled water to the solid in the filter paper.
  5. Then leave the solid to dry
• Excess solid method:

  1. Add acid to a beaker
  2. weigh out insoluble carbonate and add a bit of it to the acid.
  3. When the fizzing stops, stir it and keep adding until there is some unreacted at the bottom.
  4. Filter the solution into a conical flask to remove any unreacted carbonate.
  5. Transfer to an evaporating basin and heat the solution carefully.
  6. Stop heating when there are crystals on the edge of your basin.
  7. Leave the evaporating basin overnight for the crystals to form.
• The reactants from precipitation will always be:

  _ nitrate and sodium _.
• The reactant from titration are:

  acid and _ hydroxide
• The reactants from excess solid method are:

  acid and _ oxide or _ carbonate.