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: In the preparation of some pure crystals of Cu (NO₃)₂ starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ? Options:
  A) some CuO was reacted with excess dilute H₂SO₄
  B) the solution was concentrated
  C) when the concentrate was cooled, crystals formed were removed by filtration
  D) the crystals were washed with very little cold water
  E) the crystals were then allowed to dry
  Show Answer
  The correct answer is A .
• Question 2: When sodium reacts with water, the resulting solution is Options:
  A) Weakly acidic
  B) Neutral
  C) Acidic
  D) Alkaline
  Show Answer
  The correct answer is D .
• Question 3: Safety matches contain sulphur and? Options:
  A) potassium trioxochlorate (V)
  B) potassium trioxonitrate (V)
  C) charcoal
  D) phosphorus sulphide
  Show Answer
  The correct answer is D .
• Question 4: If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is? Options:
  A) 0.56 dm³
  B) 5.60 dm³
  C) 11.20 dm³
  D) 22.40 dm³
  Show Answer
  The correct answer is A .
• Question 5: How many coulombs of electricity are passed through a solution in which 6.5 amperes are allowed to run for 1.0 hour? Options:
  A) 3.90 x 10² coulombs
  B) 5.50 x 10³ coulombs
  C) 6.54 x 10³ coulombs
  D) 2.34 x 10⁴ coulombs
  Show Answer
  The correct answer is D .
• Question 6:

  MnO^-4_(aq) + Y + 5Fe²⁺_(aq) → Mn²⁺_(aq) + 5Fe²⁺_(aq) + 4H₂O_(l)
  In the equation above, Y is

  Options:
  A) 5H⁺_(aq)
  B) 4H⁺_(aq)
  C) 10H⁺_(aq)
  D) 8H⁺_(aq)
  Show Answer
  The correct answer is D .
• Question 7: The product formed when propanol is heated over a copper catalyst in the absence of oxygen are Options:
  A) CH₃CH₂CHO and H₂
  B) CH₃CHO and CO₂
  C) CH₃CH₂COOH and H₂
  D) CH₃COOH and CO₂
  Show Answer
  The correct answer is D .
• Question 8:

  C_(s) + H₂O_(g) → H_2(g) + CO_2(g)

  ΔG for the reaction above at 1300k is -43KJ. At this temperature, the reaction is

  Options:
  A) not feasible
  B) at equilibrium
  C) feasible
  D) exothermic
  Show Answer
  The correct answer is C .
• Question 9: Sodium metal is always kept under oil because it Options:
  A) Readily reacts with water
  B) Is reduced by atmospheric nitrogen
  C) Reacts vigorously on exposure to air
  D) Reacts with oxygen and carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 10:

  The oxidation state(s) of nitrogen in ammonium nitrite is/are

  Options:
  A) -3, +3
  B) +5
  C) -3, +5
  D) -3
  Show Answer
  The correct answer is A .