Inorganic Chemistry

Worked examples (5)

• 1Sodium added to water — observations + equation (5 marks, Paper 1)
• 2Explain the trend in reactivity down Group 1 (5 marks, Paper 1)
• 3Potassium with water — equation and observations (3 marks)
• 4Predict the properties of francium (5 marks, Paper 1)
• 5Identify Group 1 ions using flame tests (5 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — physical properties of Group 1
• ✓Model answer — 4CH1/2C-style — extended reactivity trend
• ✓Model answer — 4CH1/2C-style — comparison Group 1 vs Group 7
• ✓Model answer — 4CH1/1CR-style — storage of alkali metals

Worked examples (5)

• 1Percentage of oxygen in air — heated copper experiment (6 marks, Paper 1)
• 2Complete vs incomplete combustion of methane (5 marks, Paper 1)
• 3Formation and effects of acid rain (6 marks, Paper 2)
• 4Enhanced greenhouse effect and climate change (5 marks, Paper 2)
• 5Calculate % oxygen from experimental data (3 marks)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — composition of air
• ✓Model answer — 4CH1/2C-style — fossil fuel combustion pollution
• ✓Model answer — 4CH1/1C-style — atmospheric corrosion of iron
• ✓Model answer — 4CH1/2C-style — carbon cycle disruption

Worked examples (5)

• 1Iron nail in copper(II) sulfate — displacement reaction (5 marks, Paper 1)
• 2Required practical: investigating rusting of iron (6 marks, Paper 1)
• 3Order metals using reactions with acid and water (5 marks, Paper 1)
• 4Define oxidation and reduction in two ways (4 marks, Paper 1)
• 5Explain sacrificial protection of iron (4 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — full reactivity series
• ✓Model answer — 4CH1/1C-style — predicting displacement
• ✓Model answer — 4CH1/2C-style — redox detailed analysis
• ✓Model answer — 4CH1/2C-style — rust prevention methods

Worked examples (5)

• 1Explain why different metals are extracted differently (5 marks, Paper 1)
• 2Aluminium electrolysis — apparatus, equations and cryolite (6 marks, Paper 1)
• 3Reactions in the blast furnace (6 marks, Paper 1)
• 4Advantages of recycling aluminium (6 marks, Paper 2)
• 5Compare uses of pure copper and brass; explain alloying (5 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/2C-style — extraction method choice
• ✓Model answer — 4CH1/1CR-style — metals and uses
• ✓Model answer — 4CH1/2C-style — blast furnace operation
• ✓Model answer — 4CH1/2C-style — environmental impact of metals

Worked examples (5)

• 1Defining an acid and an alkali (3 marks, Paper 1)
• 2Strong vs weak acids — HCl vs CH₃COOH at the same concentration (4 marks, Paper 2)
• 3Titration of HCl against NaOH — apparatus and concordant titres (6 marks, Paper 1)
• 4Calculating the concentration of HCl from titration data (6 marks, Paper 2)
• 5Reactions of dilute sulfuric acid with magnesium, copper(II) oxide and calcium carbonate (5 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — full required-practical procedure
• ✓Model answer — 4CH1/2C-style — strong vs weak acid comparison (P content)
• ✓Model answer — 4CH1/1C-style — indicators and pH scale
• ✓Model answer — 4CH1/2C-style — reactions of acids

Worked examples (4)

• 1Preparing pure dry copper(II) sulfate crystals from CuO + H₂SO₄ (6 marks, Paper 1)
• 2Preparing insoluble lead(II) iodide by precipitation (5 marks, Paper 1)
• 3Applying solubility rules to predict precipitates (4 marks, Paper 1)
• 4Choosing the correct salt-preparation method for ZnSO₄ from given starting materials (5 marks, Paper 2)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — required-practical salt preparation
• ✓Model answer — 4CH1/2C-style — method choice based on solubility
• ✓Model answer — 4CH1/1C-style — solubility-rules recall
• ✓Model answer — 4CH1/2C-style — water of crystallisation

Worked examples (5)

• 1Identifying an unknown cation using NaOH (6 marks, Paper 1)
• 2Distinguishing chloride, bromide and iodide ions (5 marks, Paper 1)
• 3Identifying four common gases (4 marks, Paper 1)
• 4Identifying an unknown white solid containing a metal carbonate (5 marks, Paper 1)
• 5Testing for water — purity and presence (4 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — flame tests
• ✓Model answer — 4CH1/2C-style — anion identification scheme
• ✓Model answer — 4CH1/2C-style — combined cation + anion identification
• ✓Model answer — 4CH1/1C-style — ammonium ion test

Worked examples (4)

• 1Physical states and colours of the halogens (5 marks, Paper 1)
• 2Explaining the reactivity trend in Group 7 (5 marks, Paper 1)
• 3Predicting and explaining a halogen displacement reaction (5 marks, Paper 1)
• 4Uses of chlorine — water treatment and bleach (6 marks, Paper 2)

Model answers (5)

• ✓Model answer — 4CH1/1C-style — physical properties of halogens
• ✓Model answer — 4CH1/2C-style — Group 7 reactivity trend
• ✓Model answer — 4CH1/2C-style — halogen displacement matrix
• ✓Model answer — 4CH1/2C-style — uses of halogens with benefit/risk
• ✓Model answer — 4CH1/2C-style — Group 1 vs Group 7 comparison