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Section 2: Inorganic Chemistry Exam Practice

Edexcel IGCSE Chemistry • Exam-style Practice Questions • Structured Questions

Exam Practice

Section 2: Inorganic Chemistry Practice

Test your understanding of Inorganic Chemistry with exam-style questions. Attempt the multiple-choice section, then write your answers to the structured questions and compare them to the mark scheme.

Edexcel IGCSE Hub › Section 2 › Exam Practice

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📋 Structured Questions

These questions test key concepts from Section 2. Attempt each question on paper, then click "Show Mark Scheme" to check your answer.

Question 1: Group 1 & Group 7 Properties

4 marks

(a) Describe two observations when a small piece of sodium is added to water. [2]

(b) State the color of liquid bromine at room temperature and the observation when bromine water is added to potassium iodide solution. [2]

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(a)

Any two observations from:

  • Sodium floats / moves on the surface [1]
  • Sodium melts into a sphere / ball [1]
  • Effervescence / fizzing / bubbles of gas [1]
  • Sodium gets smaller and disappears / dissolves [1]

(b)

  • Color of bromine: Red-brown [1]
  • Observation: The solution turns brown (due to displacement forming iodine) [1]
Examiner tip: For Group 1 reactions, observations must be visible things (like floating, melting, fizzing). Saying "hydrogen gas is given off" is an inference, not an observation, though "bubbles of gas" is. For part (b), remember that iodine in solution is brown, not purple (which is only its vapour or in organic solvents).

Question 2: Percentage of Oxygen in Air

4 marks

(a) Describe a laboratory experiment using copper turnings that can be used to determine the percentage by volume of oxygen in air. [4]

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  • Place a known volume of air (e.g. 100 cm3) in one gas syringe and pass it back and forth over heated copper turnings in a glass tube [1]
  • Heat the copper strongly using a Bunsen burner [1]
  • Continue passing the air over the copper until the volume of air stops decreasing / remains constant [1]
  • Allow the apparatus to cool to room temperature, measure the final volume of gas, and calculate the percentage decrease in volume [1]
Examiner tip: Ensure you mention allowing the apparatus to cool before measuring the final volume. Gases expand when hot, so measuring while hot would lead to an incorrect volume reading.

Question 3: Displacement & Redox

4 marks

(a) Write a balanced chemical equation (including state symbols) for the displacement reaction between solid iron and aqueous copper(II) sulfate. [1]

(b) Explain, in terms of electrons, why this displacement reaction is classified as a redox reaction. [3]

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(a)

  • Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s) [1]

(b)

  • Iron atoms lose electrons (to form Fe2+ ions) and are oxidized [1]
  • Copper(II) ions (Cu2+) gain electrons (to form copper atoms) and are reduced [1]
  • Since both oxidation and reduction occur at the same time, the reaction is redox [1]
Examiner tip: Remember the mnemonic OIL RIG: Oxidation Is Loss, Reduction Is Gain of electrons. State clearly which species loses electrons and which species gains electrons. Fe is oxidized; Cu2+ (not CuSO4) is reduced.

Question 4: Metal Extraction in the Blast Furnace

3 marks

(a) In the blast furnace, iron(III) oxide (Fe2O3) is reduced to iron. Explain the role of carbon monoxide in this reduction. Include a balanced symbol equation. [3]

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  • Carbon monoxide acts as the reducing agent / reduces the iron(III) oxide [1]
  • It removes oxygen from iron(III) oxide to form carbon dioxide and iron [1]
  • Equation: Fe2O3 + 3CO → 2Fe + 3CO2 [1]
Examiner tip: Ensure the equation is fully balanced. You need 3 molecules of carbon monoxide (CO) to react with one unit of iron(III) oxide (Fe2O3), forming 2 iron atoms and 3 carbon dioxide (CO2) molecules.

Question 5: Preparing Copper(II) Sulfate

4 marks

(a) Describe how a student can prepare a pure, dry sample of hydrated copper(II) sulfate crystals starting from solid copper(II) oxide and dilute sulfuric acid. [4]

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  • Add solid copper(II) oxide in excess to warm dilute sulfuric acid until no more dissolves [1]
  • Filter the mixture to remove the unreacted copper(II) oxide solid [1]
  • Heat the copper(II) sulfate filtrate solution in an evaporating basin to evaporate some water until a saturated solution is formed / crystallisation point is reached [1]
  • Leave the solution to cool and crystallise, then filter the crystals and pat them dry with filter paper [1]
Examiner tip: Do not heat the solution to dryness. Heating to dryness would produce anhydrous copper(II) sulfate powder, not hydrated copper(II) sulfate crystals. You must heat to the "crystallisation point" (which can be tested by dipping a cold glass rod to see if crystals form on it) and then leave it to cool.

Question 6: Chemical Analysis

6 marks

(a) A student is given a bottle containing a green solid X. Describe the chemical tests the student can perform to identify the cation and the anion present in solid X. State the expected observations. [6]

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Indicative content:

  • Cation Test (Copper(II) ions, Cu2+):
    • Method 1 (Flame test): Dip a clean wire loop into hydrochloric acid, then into solid X and hold in a blue Bunsen burner flame. Observation: Green / blue-green flame.
    • Method 2 (Sodium hydroxide test): Dissolve solid X in water to make a solution. Add aqueous sodium hydroxide (NaOH). Observation: Blue precipitate of copper(II) hydroxide.
  • Anion Test (Carbonate ions, CO3 2-):
    • Method: Add dilute hydrochloric acid (HCl) to solid X or a solution of X. Observation: Effervescence / bubbles of gas.
    • Confirmation: Bubble the gas produced through limewater. Observation: Limewater turns cloudy / milky.

Marking guidance:

  • 5 to 6 marks: Describes valid chemical tests and correct observations for both the cation and the anion. Includes details of reagents used and gas confirmation if applicable.
  • 3 to 4 marks: Describes a valid test and observation for either the cation or the anion, or describes tests for both but with incorrect/missing observations.
  • 1 to 2 marks: Simple statements identifying one reagent or one correct observation.
Examiner tip: When testing for carbonate ions, simply stating "bubbles are produced" is not enough to secure the full marks. You must confirm that the gas is carbon dioxide by stating that it turns limewater cloudy.