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 1:

  The size (diameter) of five elements are in the order R < T < W < X < Y, Y being the largest. If each atom has an electron situated on its circumference, and neglecting other factors, which of the atoms will lose its electron most reluctantly?

  Options:
  A) R
  B) T
  C) W
  D) X
  E) Y
  Show Answer
  The correct answer is A .
• Question 2: Nigerian crude oil is described as light crude because of its Options:
  A) low sulphur content
  B) high natural gas content
  C) high octane number
  D) low aliphatic-hydrocarbon content
  Show Answer
  The correct answer is A .
• Question 3: Hardening of an oil may achieved by? Options:
  A) boiling the oil with water
  B) boiling the oil with a catalyst
  C) treating the oil with sodium hydroxide
  D) treating the oil with hydrogen and catalyst
  E) distilling oil under reduced pressure
  Show Answer
  The correct answer is D .
• Question 4: When marble is heated to about 1473 K, another white solid is obtained which reacts vigorously with water to give an alkaline solution. The solution contains? Options:
  A) NaOH
  B) KOH
  C) Mg(OH)₂
  D) Zn(OH)₂
  E) Ca(OH)₂
  Show Answer
  The correct answer is E .
• Question 5: A cold aqueous solution of sodium chloride is electrolyzed using a graphite anode and an iron cathode. In the course of the electrolysis the electrolyte is continuously stirred. The liquid left after electrolysis will therefore consist of? Options:
  A) sodium hydroxide solution
  B) chlorine water
  C) pure water
  D) sodium hypochlorite solution
  E) hydrochloric acid solution
  Show Answer
  The correct answer is B .
• Question 6: The reaction 3C(s) + 2Fe₂O₃(s) = 4Fe(s) + 3CO₂(g): $\mathrm{\Delta }$H =46.0 kJ is Options:
  A) isothermic
  B) adiabatic
  C) isobaric
  D) endothermic
  E) exothermic
  Show Answer
  The correct answer is D .
• Question 7:

  Stainless steel is an alloy made up of

  Options:
  A) Iron and zinc
  B) Copper and tin
  C) Iron and chromium
  D) Iron and carbon
  Show Answer
  The correct answer is C .
• Question 8: A mixture of sand, ammonium chloride and sodium chloride is best separated by? Options:
  A) sublimation followed by addition of water and filteration
  B) sublimation followed by addition of water and evaporation
  C) addition of water followed by filtration and sublimation
  D) addition of water followed by crystallization and sublimation
  Show Answer
  The correct answer is A .
• Question 9:

  Zn + H₂ SO₄ → ZnSO₄ + H₂

  In the above reaction how much Zinc will be left of 1.0 M of H₂SO?

  [Zn =65, s = 32, O = 16, H = 1]

  Options:
  A) 1.35g
  B) 1.00g
  C) 0.70g
  D) 0.65g
  E) 0.00g
  Show Answer
  The correct answer is A .
• Question 10: 2.5 g of a hydrate barium salt gave on heating, 2.13 g of the anhydrous salt. Given that the relative molecular mass of the of the anhydrous salt is 208, the number of molecules of water of crystallization of the barium salt is Options:
  A) 10
  B) 7
  C) 5
  D) 2
  E) 1
  Show Answer
  The correct answer is D .