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: An elements used in production of matches is Options:
  A) nitrogen
  B) aluminum
  C) copper
  D) sulphur
  Show Answer
  The correct answer is D .
• Question 2:

  If the cost of electricity required to discharge 10g of an ion X${}^{3+}$ is N20.00, how much would it cost to discharge 6g of ion Y${}^{2+}$?

  [1 faraday = 96,500C, atomic masses are X = 27, Y = 24]

  Options:
  A) N10.00
  B) N6.00
  C) N20.00
  D) N9.00
  Show Answer
  The correct answer is D .
• Question 3: The nucleus of the isotopes tritium contains Options:
  A) two neutrons with no protons
  B) one neutron and one proton
  C) two neutrons and one proton
  D) two neutrons, one proton and one electron
  Show Answer
  The correct answer is C .
• Question 4: Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution? Options:
  A) (NH₄)CO₃
  B) ZnCO₃
  C) Al₂(SO₄)₃
  D) PbCO3
  Show Answer
  The correct answer is B .
• Question 5: Mineral acids are usually added to commercial hydrogen peroxide to Options:
  A) oxidize it
  B) decompose it
  C) minimize its decomposition
  D) reduce it to water and oxygen
  Show Answer
  The correct answer is C .
• Question 6: Which of the following is formed when maltose reacts with concentrated tetraoxosulphate (VI) acid ? Options:
  A) Carbon (IV) oxide
  B) Coal tar
  C) Charcoal
  D) Toxic fumes
  Show Answer
  The correct answer is C .
• Question 7: A solution which on treatment with hydrochloric acid produces a colourless, odourless gas which turns lime water milky is most likely to be a Options:
  A) trioxonitrate (V)
  B) chloride
  C) trioxocarbonate (IV)
  D) hydroxide
  Show Answer
  The correct answer is C .
• Question 8:

  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 9:

  Which of the following is an example of an endothermic reaction?

  Options:
  A) Combustion of propane (C${}_3$H${}_8$) to produce carbon dioxide (CO${}_2$) and water (H${}_2$O).
  B) Burning of methane (CH${}_4$) in the presence of oxygen
  C) Formation of table salt (NaCl) from sodium (Na) and chlorine (Cl${}_2$).
  D) Decomposition of hydrogen peroxide (H${}_2$O${}_2$) into water (H${}_2$O) and oxygen (O${}_2$).
  Show Answer
  The correct answer is D .
• Question 10:

  

  The diagram represents

  Options:
  A) A spontaneous reaction
  B) An exothermic reaction
  C) A non-spontaneous
  D) An endothermic reaction
  Show Answer
  The correct answer is C .