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 981: During the vulcanization of rubber, sulphur is added to Options:
  A) Break down rubber polymer
  B) Lengthen the chain of rubber
  C) Bind rubber molecules together
  D) Act as a catalyst
  Show Answer
  The correct answer is C .
• Question 982: A mixture of iodine and sulphur crystals can be separated by treatment with Options:
  A) Water to filter off sulphur
  B) carbon (IV) sulphide to filter off iodine
  C) ethanoic acid to filter off sulphur
  D) methanol to filter off iodine
  Show Answer
  The correct answer is B .
• Question 983:

  Pure sulphuric acid is a liquid of 1:84 density. What volume of it would be required to prepare 250 cm³ of 2.0 M solution?

  (H = 1, S = 32, O = 16)

  Options:
  A) 2.00
  B) 2.66
  C) 3.00
  D) 3.66
  E) 4.00
  Show Answer
  The correct answer is B .
• Question 984:

  In the reaction H_2(g)O $\to$ H_2(g) + 1/2O_2(g)

  ΔH = -2436000 KJ, which of the following has no effect on the equilibrium position?

  Options:
  A) Adding argon to the system
  B) Lowering the temperature
  C) Adding hydrogen to the system
  D) Decreasing the pressure
  E) Increasing the temperature
  Show Answer
  The correct answer is A .
• Question 985: If the silver mirror test is positive, it indicates the presence of an Options:
  A) alkyne
  B) alkanol
  C) alkanone
  D) alkanal
  Show Answer
  The correct answer is D .
• Question 986: Which of the following statements is NOT correct? Options:
  A) The average kinetic energy of a gas is directly proportional to its temperature
  B) At constant tempearture, the volume of a gas increases as the pressure increases
  C) The pressure of a gas is inversely proportional to its volume
  D) The temperature of a gas is directly proportional to its volume
  E) The collisions of molecules with each other are inelastic
  Show Answer
  The correct answer is B .
• Question 987:

  If the heat of combustion of hydrogen is -285.8kJ,

  What is the heat of formation of water?

  Options:
  A) +571.6 kJ
  B) -571.6 kJ
  C) -285.8 kJ
  D) +285.8 kJ
  Show Answer
  The correct answer is C .
• Question 988:

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  Options:
  A) 24,125 C
  B) 48,250 C
  C) 72,375 C
  D) 96,500 C
  Show Answer
  The correct answer is B .
• Question 989: H ₂O _(g) + C _(s) → H_2(g) + CO_(g)The oxidizing agent in the reaction above is Options:
  A) CO_(g)
  B) C_(s)
  C) H₂O_(g)
  D) H_(2)(g)
  Show Answer
  The correct answer is C .
• Question 990: 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 .