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: When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are; Options:
  A) nitrogen and carbondioxide
  B) the rare gases
  C) nitrogen and oxygen
  D) nitrogen and the rare gases
  E) nitrogen, carbondioxide and the rare gases
  Show Answer
  The correct answer is D .
• Question 802: What is the volume of oxygen required to burn complete 45 cm³ of methane at s.t.p? Options:
  A) 135.0 cm³
  B) 180.0 cm³
  C) 45.0 cm³
  D) 90.0 cm³
  Show Answer
  The correct answer is D .
• Question 803: The weakest attractive force that can be observed between two molecules is Options:
  A) ionic
  B) covalent
  C) coordinate covalent
  D) van der Waals
  Show Answer
  The correct answer is D .
• Question 804: The reaction of zinc with copper (ll) ions in aqueous solution can be represented as follows: Cu ²⁺(aq) +Zn (s) → Cu(s) + Zn ²⁺(aq).Which of the following is the most complete description of this reaction? Options:
  A) Cpper (ll) ions are being reduced
  B) Zinc is being oxidized.
  C) Copper (ll) ions and zinc are being reduced
  D) copper (ll) ions and zinc are being oxidized
  E) copper(ll) ions are being reduced and zinc oxidized
  Show Answer
  The correct answer is E .
• Question 805: A metal M displaces zinc from zinc chloride solution. This shows that Options:
  A) M is more electronegative than zinc
  B) Zinc is above hydrogen in the series
  C) M is more electropositive than zinc
  D) Electrons flow from zinc to M
  Show Answer
  The correct answer is C .
• Question 806:

  Which of the following methods is commonly used to remove suspended impurities from water?

  Options:
  A) Fluoridation
  B) Chlorination
  C) Filtration
  D) Distillation
  Show Answer
  The correct answer is C .
• Question 807: Which of the following reactions is correct as as written? Options:
  A) FeCl₂ + 3NH₄OH → Fe(OH)₃ + 3NH₄Cl
  B) Pb₂O₃ + 4HCl → PbCl₂ + 2H₂O
  C) PbNO₃ + H₂S → PbS + 2HNO₃
  D) NaOH + H₂SO₄ → NaHSO₄ +H₂O
  E) 2NH₄NO₃ → N₂ + 2H₂O
  Show Answer
  The correct answer is D .
• Question 808: 2.25g of a sample of an oxide of copper on reduction gave 2.0g of copper. 2.50g of another oxide of copper on reduction also gave 2.0g of copper. These results are in accordance with the law of? Options:
  A) constant composition
  B) conservation of matter
  C) multiple proportions
  D) definite proportions
  Show Answer
  The correct answer is C .
• Question 809: Detergents are manufacture with strength hydrocarbon chains is to make them Options:
  A) soluble
  B) biodegradable
  C) cheaper
  D) foamy
  Show Answer
  The correct answer is B .
• Question 810: A liquid begins to boil when? Options:
  A) its vapour pressure is equal to the vapour pressure of its solid at the given temperature
  B) molecules start escaping from its surface
  C) its vapour pressure equals the atmosphere pressure
  D) its volume is sightly increased
  Show Answer
  The correct answer is C .