Skip to content

WAEC WASSCE 2015

WAEC Chemistry 2015 past questions

6 objective questions from the 2015 WAEC Chemistry paper. Answer each one, then reveal the answer and explanation.

All WAEC Chemistry past questions

  1. Question 1

    Atomic structure

    An atom of aluminium has atomic number 13 and mass number 27. How many neutrons are in its nucleus?

    1. Option A: 14
    2. Option B: 27
    3. Option C: 13
    4. Option D: 40
    Show the answer to question 1

    Answer: A, 14

    Neutrons = mass number − atomic number = 27 − 13 = 14.

  2. Question 2

    Electronic configuration

    What is the electronic configuration of silicon (atomic number 14)?

    1. Option A: 2, 8, 4
    2. Option B: 2, 8, 3
    3. Option C: 2, 8, 5
    4. Option D: 2, 8, 6
    Show the answer to question 2

    Answer: A, 2, 8, 4

    Fill the shells in order, 2 then 8 then 8: silicon has 14 electrons, arranged 2, 8, 4.

  3. Question 3

    Gas laws

    A fixed mass of gas occupies 600 cm³ at a pressure of 4 atm. What volume will it occupy at 8 atm if the temperature stays constant?

    1. Option A: 1200 cm³
    2. Option B: 600 cm³
    3. Option C: 300 cm³
    4. Option D: 19200 cm³
    Show the answer to question 3

    Answer: C, 300 cm³

    By Boyle's law, P₁V₁ = P₂V₂, so V₂ = 4 × 600 ÷ 8 = 300 cm³.

  4. Question 4

    Mole concept

    How many moles are there in 900 g of glucose (C₆H₁₂O₆)? [C = 12, H = 1, O = 16]

    1. Option A: 10 mol
    2. Option B: 2.5 mol
    3. Option C: 50 mol
    4. Option D: 5 mol
    Show the answer to question 4

    Answer: D, 5 mol

    Moles = mass ÷ molar mass = 900 ÷ 180 = 5 mol.

  5. Question 5

    Organic chemistry

    What is the molecular formula of pentene?

    1. Option A: C₅H₁₂
    2. Option B: C₅H₈
    3. Option C: C₅H₁₀
    4. Option D: C₅H₁₁
    Show the answer to question 5

    Answer: C, C₅H₁₀

    Alkenes follow CₙH₂ₙ, so pentene with 5 carbon atoms is C₅H₁₀.

  6. Question 6

    Acids, bases and salts

    Phenolphthalein in an alkaline solution is

    1. Option A: colourless
    2. Option B: yellow
    3. Option C: blue
    4. Option D: pink
    Show the answer to question 6

    Answer: D, pink

    Phenolphthalein is colourless in acid and pink in alkali.

Practise WAEC Chemistry on SchoolEasy CBT

In SchoolEasy, students answer timed questions on screen, see an explanation for every answer, and track their progress topic by topic. Teachers turn past questions into class tests that mark themselves.

Practise in the appRequest a demo for your school

School management made effortless.

We strive to build the best school management software for schools from all over the world.

Available soon on all digital platforms

Download on theApp StoreGet it onGoogle Play