Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 341: The gas that is most useful in protecting humans against solar radiation is Options:
  A) chlorine
  B) ozone
  C) carbon (IV) oxide
  D) hydrogen sulphide
  Show Answer
  The correct answer is B .
• Question 342:

  The maximum electron in N shell is?

  Options:
  A) 2
  B) 8
  C) 18
  D) 32
  Show Answer
  The correct answer is D .
• Question 343: Synthetic rubber is made by polymerization of? Options:
  A) 2 methyl buta - 1, 3 - diene
  B) 2 methyl buta - 1, 2 - diene
  C) 2 methyl but -1-ene
  D) 2 methyl but-2-ene
  Show Answer
  The correct answer is A .
• Question 344:

  

  In the diagram above the activation energy is represented by

  Options:
  A) y - x
  B) x
  C) x - z
  D) y
  Show Answer
  The correct answer is A .
• Question 345:

  Which functional group is present in alkanals?

  Options:
  A) Carbonyl group (C=O)
  B) Hydroxyl group (-OH)
  C) Alkyl group (-R)
  D) Carboxyl group (-COOH)
  Show Answer
  The correct answer is A .
• Question 346:

  If one mole of aluminium contains 6 x 10²³ atoms of aluminium, how many atoms are contained in 0.9g of aluminium?

  (Al = 27)

  Options:
  A) 1.0 x 10²¹
  B) 6.6 x 10²¹
  C) 2.0 x 10²²
  D) 1.0 x 10²²
  E) 5.4 x 10²³
  Show Answer
  The correct answer is C .
• Question 347:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
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  The correct answer is B .
• Question 348: The most common type of chemical reaction which alkanes undergo is Options:
  A) substitution
  B) addition
  C) condensation
  D) polymerisation
  E) double decomposition
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  The correct answer is A .
• Question 349: The balanced equation for the reaction of tetraoxosulphate(VI)acid with aluminium hydroxide to give water and aluminium tetraoxosulphate(VI) is Options:
  A) H₂SO₄ + Al(OH)₂ $\to$ 2H₂O + AlSO₄
  B) 3H₂SO₄ + 2Al(OH)₃ $\to$ 6H₂O + Al₂(SO₄)₃
  C) 3H₂SO₄ + 2AlH $\to$ 6H₂O + Al(SO₄)₃
  D) 3H₂ SO₄ + 2Al(OH)₃ $\to$ Al(SO₄)₃
  E) H₂SO₄ + Al(OH)₃ $\to$ H₂O + Al₂(SO₄)₃
  Show Answer
  The correct answer is B .
• Question 350: Which of the following is NOT true of metals? Options:
  A) They are good conductors of electricity
  B) They ionize by electron loss
  C) Their oxides are acidic
  D) They have high melting points
  Show Answer
  The correct answer is C .