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 1131:

  What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

  [H = 1, O = 16]

  Options:
  A) 36.0g
  B) 8.0g
  C) 72.0g
  D) 16.0g
  Show Answer
  The correct answer is C .
• Question 1132: The monomer of nylon is Options:
  A) Hydroxybenzene
  B) Hexanedioic acid
  C) Benzene -1,-4-dicarboxylic acid
  D) Ethane-1,2-diol
  Show Answer
  The correct answer is B .
• Question 1133: The chemicals used to soften hard water involves the addition of Options:
  A) insoluble sodium compounds which from soluble solutions of calcium and magesium
  B) solube soudium compounds which from soluble solutions of calcium and magnesium ions
  C) solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
  D) insoluble precipitates of calcium and magnesium ions
  Show Answer
  The correct answer is C .
• Question 1134:

  

  In the graph above, the activation energy of the catalyzed reaction is

  Options:
  A) 100KJ
  B) 300KJ
  C) 250KJ
  D) 200KJ
  Show Answer
  The correct answer is A .
• Question 1135: An organic compound decolourized acidified KMnO₄ solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be? Options:
  A) a carbonxylic acid
  B) an alkane
  C) an alkene
  D) an alkyne
  E) an akanone
  Show Answer
  The correct answer is C .
• Question 1136: An anhydride is an oxide of non-mental? Options:
  A) which will not dissolve in water
  B) whose solution in water has a pH greater than 7
  C) whose solution in water has a pH less than 7
  D) whose solution in water has a pH of 7
  Show Answer
  The correct answer is C .
• Question 1137: An oxide XO₂ has a vapour density of 32. What is the atomic mass of X? Options:
  A) 20
  B) 32
  C) 14
  D) 12
  Show Answer
  The correct answer is B .
• Question 1138:

  

  An experiment test of the Law of conservation of Mass is illustrated in the diagram. In practice, the flask is weighed before and after reaction between solutions X and Y. Which of the following pairs of solutions will be unsuitable for the experiments

  Options:
  A) X = hydrochloric acid; Y = silver nitrate
  B) X = barium chloride; Y = dilute sulphuric acid
  C) X = hydrochloric acid; Y = sodium hydroxide
  D) X = hydrochloric acid; Y = lead nitrate
  E) X = hydrochloric acid; Y = sodium carbonate
  Show Answer
  The correct answer is E .
• Question 1139: 50 cm³ of gas was collected over water at 10^oC and 765 mm Hg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10 ^oC is 5mm Hg Options:
  A) 49.19 cm ³
  B) 48.87 cm ³
  C) 48.55 cm ³
  D) 48.23 cm ³
  Show Answer
  The correct answer is D .
• Question 1140: 2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of? Options:
  A) constant composition
  B) conservation of mass
  C) reciprocal proportions
  D) multiple proportions
  Show Answer
  The correct answer is D .