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UTME 2024

JAMB Chemistry past questions and answers

10 questions from the most recent UTME Chemistry papers in our bank, across different topics. Try each one, then open the answer to see a worked solution.

  1. Question 1 · UTME 2024 · Separation of Mixtures and Purification

    Fog is a colloid in which

    1. Aliquid particles are dispersed in a gas medium
    2. Bgas particles are dispersed in a liquid medium
    3. Csolid particles are dispersed in a gas medium
    4. Dgas particles are dispersed in a solid medium
    Show answer and solution

    Answer: A. liquid particles are dispersed in a gas medium

    What the question is asking: Composition of fog.

    Key idea: Fog consists of tiny water droplets (liquid) dispersed in air (gas) — a liquid aerosol. Solid in gas is smoke; gas in liquid is foam.

  2. Question 2 · UTME 2024 · Atomic Structure and Bonding

    The scientist whose experiments with discharge tubes led to the identification of cathode rays as streams of sub-atomic particles (electrons) is

    1. AJ. J. Thomson
    2. BRobert Millikan
    3. CErnest Rutherford
    4. DNiels Bohr
    Show answer and solution

    Answer: A. J. J. Thomson

    What the question is asking: Discoverer of the electron.

    Key idea: In 1897 Thomson deflected cathode rays with electric and magnetic fields and measured their charge-to-mass ratio, showing they were negatively charged particles — electrons. Millikan later measured the electron's charge.

  3. Question 3 · UTME 2024 · Water

    In the treatment of water for municipal supply, chlorine is used to

    1. Aprevent tooth decay
    2. Bprevent goitre
    3. Ckill germs
    4. Dremove colour or odour
    Show answer and solution

    Answer: C. kill germs

    What the question is asking: Purpose of chlorination.

    Key idea: Chlorine forms HOCl in water, which kills bacteria and other micro-organisms (disinfection). Fluoride prevents tooth decay; charcoal removes colour and odour.

  4. Question 4 · UTME 2024 · Chemical Combination and Stoichiometry

    Determine the empirical formula of an oxide of sulphur containing 60% oxygen. [S = 32, O = 16]

    1. ASO₃
    2. BSO₂
    3. CSO₄
    4. DSO
    Show answer and solution

    Answer: A. SO₃

    What the question is asking: Simplest ratio of S : O.

    Step 1 – S = 100 − 60 = 40%

    Step 2 – S: 40/32 = 1.25; O: 60/16 = 3.75

    Step 3 – Divide by 1.25: 1 : 3 → SO₃

  5. Question 5 · UTME 2024 · Environmental Pollution

    Which of the following is an air pollutant?

    1. AO₂
    2. BCO
    3. CH₂O(g)
    4. DN₂
    Show answer and solution

    Answer: B. CO

    What the question is asking: Harmful gas in air.

    Key idea: Carbon(II) oxide, from incomplete combustion, is poisonous: it combines with haemoglobin and stops oxygen transport. O₂, N₂ and water vapour are normal, harmless components of air.

  6. Question 6 · UTME 2024 · Energy Changes

    For a chemical reaction to be spontaneous, ΔG must be

    1. Apositive
    2. Bnegative
    3. Czero
    4. Dequal to the enthalpy change
    Show answer and solution

    Answer: B. negative

    What the question is asking: Condition for spontaneity.

    Key idea: ΔG < 0: spontaneous; ΔG > 0: non-spontaneous; ΔG = 0: at equilibrium.

  7. Question 7 · UTME 2024 · Metals and Their Compounds

    The constituents of Alnico are aluminium, nickel, iron and

    1. AMg
    2. BCo
    3. CMn
    4. DCu
    Show answer and solution

    Answer: B. Co

    What the question is asking: Composition of Alnico.

    Key idea: The name comes from Al–Ni–Co: aluminium, nickel and cobalt, alloyed with iron. It is used for permanent magnets.

  8. Question 8 · UTME 2024 · Hydrocarbons

    The empirical formula of a liquid hydrocarbon is XY. If the relative masses of X and Y in the formula are 72 and 6 respectively, its vapour density is likely to be

    1. A33
    2. B66
    3. C39
    4. D78
    Show answer and solution

    Answer: C. 39

    What the question is asking: Vapour density from the formula mass.

    Step 1 – Formula mass of XY = 72 + 6 = 78 (this is C₆H₆, benzene: 6 × 12 = 72 and 6 × 1 = 6)

    Step 2 – Taking the molecular mass as 78, VD = 78/2 = 39

    Common trap: 78 is the molar mass, not the vapour density.

  9. Question 9 · UTME 2024 · Acids, Bases and Salts

    The pH of a 0.001 mol dm⁻³ solution of H₂SO₄ is [log₁₀ 2 = 0.3]

    1. A2.7
    2. B3.0
    3. C3.3
    4. D2.0
    Show answer and solution

    Answer: A. 2.7

    What the question is asking: pH of a dibasic strong acid.

    Step 1 – [H⁺] = 2 × 0.001 = 0.002 = 2 × 10⁻³ mol dm⁻³

    Step 2 – pH = −log(2 × 10⁻³) = 3 − 0.3 = 2.7

  10. Question 10 · UTME 2024 · Electrolysis

    The quantity of electricity required to deposit 180 g of Ag from molten silver trioxonitrate(V) is [Ag = 108]

    1. A1.08 F
    2. B3.30 F
    3. C1.67 F
    4. D1.80 F
    Show answer and solution

    Answer: C. 1.67 F

    What the question is asking: Faradays for silver.

    Key idea: Ag⁺ + e⁻ → Ag: 1 F per mole of Ag.

    Step 1 – Moles Ag = 180/108 = 1.67 mol

    Step 2 – Charge = 1.67 F

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