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 61: The reaction of an alkanol with an alkanoic acid in the presence of concentrated H₂SO₄ will produce an? Options:
  A) alkanal
  B) alkanoate
  C) alkanone
  D) alkyne
  Show Answer
  The correct answer is B .
• Question 62: A side effect of soft water is that Options:
  A) it gives offensive taste
  B) excess calcium is precipitated
  C) it attacks lead contained in pipes
  D) it encourage the growth of bacteria
  Show Answer
  The correct answer is C .
• Question 63:

  The Consecutive members of an alkane homologous series differ by

  Options:
  A) CH
  B) CH${}_2$
  C) CH${}_3$
  D) C${}_n$H${}_n$
  Show Answer
  The correct answer is B .
• Question 64:

  The part of the total energy of a system that accounts for the useful work done in a system is known as

  Options:
  A) Enthalpy change
  B) None of the above
  C) Gibb's free energy
  D) Entropy
  Show Answer
  The correct answer is C .
• Question 65:

  C_(s) + H₂O_(g) → H_2(g) + CO_2(g)

  ΔG for the reaction above at 1300k is -43KJ. At this temperature, the reaction is

  Options:
  A) not feasible
  B) at equilibrium
  C) feasible
  D) exothermic
  Show Answer
  The correct answer is C .
• Question 66:

  What is the maximum number of electrons that can occupy the second energy level (n=2)?

  Options:
  A) 2 electrons
  B) 18 electrons
  C) 8 electrons
  D) 32 electrons
  Show Answer
  The correct answer is C .
• Question 67: A metallic ion X²⁺ with an inert gas structure contains 18 electrons. How many protons are there in this ion? Options:
  A) 20
  B) 18
  C) 16
  D) 2
  Show Answer
  The correct answer is A .
• Question 68:

  Balance the following redox reaction:
  Fe${}_2$O${}_3$+ CO Fe + CO${}_2$

  Options:
  A) Fe${}_2$O${}_3$ + CO → 2Fe + 2CO${}_2$
  B) 2Fe${}_2$O${}_3$ + 3CO → 4Fe + 3CO${}_2$
  C) Fe${}_2$O${}_3$ + 2CO → 2Fe + 2CO${}_2$
  D) Fe${}_2$O${}_3$ + 3CO → 2Fe + 3CO${}_2$
  Show Answer
  The correct answer is D .
• Question 69:

  

  Use the diagram above to answer this question.

  Which of the following structural formula is NOT isomeric with the others?

  Options:
  A) A
  B) B
  C) C
  D) D
  E) E
  Show Answer
  The correct answer is D .
• Question 70: Calculate the volume of carbon (IV)oxide measured at s.t.p, produced when 1 kg of potassium hydrogen trioxocarbonate (IV) is totally decomposed by heat?(G.M.V. at s.t.p 22.4 dm³, K = 39, O = 16, C = 12, H = 1) Options:
  A) 28 dm³
  B) 56 dm³
  C) 112 dm³
  D) 196 dm³
  Show Answer
  The correct answer is C .