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 121: A common characteristic between zinc and the other transition elements is the ability to Options:
  A) have variable oxidation states
  B) from complex ions
  C) act as a catalyst
  D) from coloured ions
  Show Answer
  The correct answer is B .
• Question 122: In the manufacture of iron in the blast furnace, iron (lll) oxide is mixed with coke and limestone, and different reactions occur in the process. Which of the following statements is true with respect to these reactions? Options:
  A) the coke is a powerful reducing agent and easily converts the iron oxide to iron
  B) the calcuim carbonate reacts with SiO₂ an earthly impurity in the ore, to from calcuim silicate
  C) the coke will react with the iron produced to form steel
  D) all the carbondioxide required in the process comes from the decomposition of the calcium carbonate
  E) the calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity
  Show Answer
  The correct answer is E .
• Question 123: In which of the following reactions does reduction takes place Options:
  A) Fe²⁺ - e^- → Fe³⁺
  B) 2O^2- →O₂ + 4e^-
  C) Cr – 2e^- → Cr²⁺
  D) 2H⁺ + 2e^- → H₂
  Show Answer
  The correct answer is D .
• Question 124: According to the kinetic theory an absence in temperature causes the kinetic energy of particles to Options:
  A) decrease
  B) increase
  C) remain constant
  D) be zero
  Show Answer
  The correct answer is D .
• Question 125: Which of the following compounds is a neutral oxide? Options:
  A) Carbon (IV) oxide
  B) Sulphur (Vl) oixide
  C) Sulphur (IV) oxide
  D) Carbon (ll) oxide
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  The correct answer is D .
• Question 126: Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains Options:
  A) water vapour
  B) oxygen
  C) carbon (IV) oxide
  D) rare gases
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  The correct answer is D .
• Question 127:

  Given that 15.00 cm³ of H₂

  SO₄ was required to completely neutralize 25.00 cm³ of 0.125 mol dm^-3 NaOH, calculate the molar concentration of the acid solution:

  Options:
  A) 0.925 mol dm^-3
  B) 0.156mol dm^-3
  C) 0.104 mol dm^-3
  D) 0.023 mol dm^-3
  Show Answer
  The correct answer is C .
• Question 128: Which of the following contains two amphoteric oxides? Options:
  A) sodium oxide, Zinc oxide , Magnesium oxide
  B) Aluminium oxide, Calcium oxide, Zinc oxide
  C) Potassium oxide, Lithium oxide, Carbon monoxide
  D) Silver oxide, Lead oxide, Sodium oxide
  E) Sulphur dioxide, Aluminium oxide, Carbon monoxide
  Show Answer
  The correct answer is B .
• Question 129:

  Which of the following alkaline metals react more quickly spontaneously with water?

  Options:
  A) Calcium
  B) Beryllium
  C) Magnesium
  D) Strontium
  Show Answer
  The correct answer is A .
• Question 130: The oxidation state of oxygen in tetraoxosulphate (VI) acid is Options:
  A) -4
  B) -2
  C) +4
  D) -8
  Show Answer
  The correct answer is B .