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JAMB UTME

JAMB Chemistry past questions and answers

Objective Chemistry questions from past JAMB UTME papers, with the answer and a short explanation for each. Try a question, then reveal the answer to check your working.

  1. Question 1

    JAMB 2024Gas laws

    A fixed mass of gas occupies 120 cm³ at a pressure of 3 atm. What volume will it occupy at 1 atm if the temperature stays constant?

    1. Option A: 40 cm³
    2. Option B: 360 cm³
    3. Option C: 120 cm³
    4. Option D: 720 cm³
    Show the answer to question 1

    Answer: B, 360 cm³

    By Boyle's law, P₁V₁ = P₂V₂, so V₂ = 3 × 120 ÷ 1 = 360 cm³.

  2. Question 2

    JAMB 2024Electronic configuration

    What is the electronic configuration of neon (atomic number 10)?

    1. Option A: 2, 7
    2. Option B: 2, 8, 1
    3. Option C: 2, 8, 2
    4. Option D: 2, 8
    Show the answer to question 2

    Answer: D, 2, 8

    Fill the shells in order, 2 then 8 then 8: neon has 10 electrons, arranged 2, 8.

  3. Question 3

    JAMB 2024Acids, bases and salts

    What is the pH of a neutral solution at 25 °C?

    1. Option A: 0
    2. Option B: 7
    3. Option C: 14
    4. Option D: 1
    Show the answer to question 3

    Answer: B, 7

    A neutral solution has pH 7.

  4. Question 4

    JAMB 2024Organic chemistry

    What is the molecular formula of hexane?

    1. Option A: C₆H₁₂
    2. Option B: C₆H₁₀
    3. Option C: C₆H₁₃
    4. Option D: C₆H₁₄
    Show the answer to question 4

    Answer: D, C₆H₁₄

    Alkanes follow CₙH₂ₙ₊₂, so hexane with 6 carbon atoms is C₆H₁₄.

  5. Question 5

    JAMB 2024Atomic structure

    An atom of fluorine has atomic number 9 and mass number 19. How many neutrons are in its nucleus?

    1. Option A: 19
    2. Option B: 9
    3. Option C: 28
    4. Option D: 10
    Show the answer to question 5

    Answer: D, 10

    Neutrons = mass number − atomic number = 19 − 9 = 10.

  6. Question 6

    JAMB 2023Chemical symbols

    What is the chemical symbol of manganese?

    1. Option A: Mn
    2. Option B: Mg
    3. Option C: Ma
    4. Option D: M
    Show the answer to question 6

    Answer: A, Mn

    Manganese is Mn; Mg is magnesium.

  7. Question 7

    JAMB 2023Atomic structure

    An atom of carbon has atomic number 6 and mass number 12. How many neutrons are in its nucleus?

    1. Option A: 12
    2. Option B: 6
    3. Option C: 18
    4. Option D: 7
    Show the answer to question 7

    Answer: B, 6

    Neutrons = mass number − atomic number = 12 − 6 = 6.

  8. Question 8

    JAMB 2023Organic chemistry

    What is the molecular formula of pentane?

    1. Option A: C₅H₁₀
    2. Option B: C₅H₈
    3. Option C: C₅H₁₂
    4. Option D: C₅H₁₁
    Show the answer to question 8

    Answer: C, C₅H₁₂

    Alkanes follow CₙH₂ₙ₊₂, so pentane with 5 carbon atoms is C₅H₁₂.

  9. Question 9

    JAMB 2023Gas laws

    A fixed mass of gas occupies 60 cm³ at a pressure of 2 atm. What volume will it occupy at 4 atm if the temperature stays constant?

    1. Option A: 120 cm³
    2. Option B: 60 cm³
    3. Option C: 30 cm³
    4. Option D: 480 cm³
    Show the answer to question 9

    Answer: C, 30 cm³

    By Boyle's law, P₁V₁ = P₂V₂, so V₂ = 2 × 60 ÷ 4 = 30 cm³.

  10. Question 10

    JAMB 2023Electronic configuration

    What is the electronic configuration of boron (atomic number 5)?

    1. Option A: 2, 2
    2. Option B: 2, 4
    3. Option C: 2, 3
    4. Option D: 2, 5
    Show the answer to question 10

    Answer: C, 2, 3

    Fill the shells in order, 2 then 8 then 8: boron has 5 electrons, arranged 2, 3.

More Chemistry: WAEC Chemistry past questions.

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