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 801: 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 802: How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?(Ni = 58.7, 1F = 96 500 C mol^-) Options:
  A) 0.20
  B) 0.30
  C) 0.40
  D) 0.50
  Show Answer
  The correct answer is C .
• Question 803:

  At 27°C, 58.5g of sodium chloride is present in 250cm${}^3$ of a solution. The solubility of sodium chloride at this temperature is?

  (molar mass of sodium chloride = 111.0gmol${}^{-1}$)

  Options:
  A) 2.0 moldm${}^{-3}$
  B) 0.25 moldm${}^{-3}$
  C) 1.0 moldm${}^{-3}$
  D) 0.5 moldm${}^{-3}$
  Show Answer
  The correct answer is A .
• Question 804:

  Which of the following is a physical change?

  Options:
  A) Exposing white phosphorus to air
  B) Burning kerosene
  C) Dissolving calcium in water
  D) Freezing ice cream
  Show Answer
  The correct answer is D .
• Question 805:

  In the reaction:

  M + N → P

  ΔH = +Q kJWhich of the following would increase the concentration of the product?

  Options:
  A) Adding a suitable catalyst
  B) Increasing the concentration of P
  C) Increasing the temperature
  D) Decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 806: The substance least considered as a source of environmental pollution is Options:
  A) Lead compounds
  B) Organophosphorous compounds
  C) Silicate minerals
  D) Uranium
  Show Answer
  The correct answer is C .
• Question 807: Which of the following sets of metals dissolves in dilute HCl? Options:
  A) Fe, Sn and Cu
  B) Mg, Fe and Cu
  C) Mg, Sn and Fe
  D) Cu, Mg and Sn
  Show Answer
  The correct answer is C .
• Question 808: In the discovery of protein, the instrument used is Options:
  A) cathode ray tube
  B) glass tube and discharge tube
  C) discharge tube with terminal cathode
  D) discharge tube with central cathode
  Show Answer
  The correct answer is D .
• Question 809: In the extraction of iron in the blast furnace, limestone is used to? Options:
  A) release CO₂ for the reaction
  B) reduce the iron ore
  C) increase the strenght of the iron
  D) remove impurities
  Show Answer
  The correct answer is D .
• Question 810: A saturated solution of AgCl was found to have a concentration of 1.30 x 10^-5 mol dm^-3. The solubility product of AgCl therefore is? Options:
  A) 1.30 x 10^-5 mol₂ dm^-6
  B) 1.30 x 10^-7 mol₂ dm^-6
  C) 1.69 x 10^-10 mol₂ dm^-6
  D) 2.60 x 10^-12 mol₂ dm^-6
  Show Answer
  The correct answer is C .