Acids, Bases and Salts

Worked examples (12)extended set

• 1Using the pH scale and indicator colours
• 2Three typical reactions of hydrochloric acid
• 3Bases, alkalis and the test for ammonium ions
• 4Proton donor or proton acceptor? (multiple choice)
• 5Strong or weak? Degree of dissociation (multiple choice)
• 6Strong and weak acids reacting with magnesium
• 7Observations when a carbonate reacts with an acid
• 8Reading a pH curve for neutralisation
• 9Identifying four unknown solutions
• 10Deducing how many hydrogen ions an acid releases
• 11Why lime and ammonium fertiliser should not be mixed
• 12Purity of limestone from the volume of carbon dioxide

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style

Worked examples (12)extended set

• 1Picking acidic, basic and amphoteric oxides from a list
• 2Burning two elements in oxygen and testing the oxides
• 3Choosing the correct row of oxides (multiple choice)
• 4Zinc oxide as an amphoteric oxide: two equations
• 5Deducing the type of element from its oxide (multiple choice)
• 6Classifying four unknown oxides from test results
• 7Copper(II) oxide as a base: observations, ionic equation and mass
• 8Aluminium oxide with nitric acid: formula, equation and yield
• 9Measuring carbon dioxide with a gas syringe and alkali
• 10The oxides of Period 3: reading a pH bar chart
• 11Identifying an amphoteric oxide from ion tests
• 12Using an amphoteric oxide to find the purity of an ore

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style

Worked examples (12)extended set

• 1Applying the solubility rules
• 2Magnesium sulfate from excess magnesium carbonate
• 3Method for a pure, dry insoluble salt (multiple choice)
• 4Choosing reactants for a precipitation (multiple choice)
• 5Finding the water of crystallisation in a hydrated salt
• 6Potassium nitrate by titration
• 7Barium carbonate by precipitation: yield too high
• 8Crystals from a solubility curve
• 9Zinc chloride: why excess solid, and which other reactants
• 10Planning: hydrated crystals from a slow-reacting oxide
• 11Percentage yield of hydrated zinc sulfate crystals
• 12Identifying four unlabelled solutions from a precipitation grid

Model answers (6)

• ✓Model answer — Paper 4 short-answer style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 4 (Extended) structured style
• ✓Model answer — Paper 6 (Alternative to Practical) style
• ✓Model answer — Paper 6 (Alternative to Practical) style