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:

  ₁²D + ₁³T → ₂⁴He + ₀¹n + energy

  The reaction above illustrates

  Options:
  A) alpha decay
  B) artificial transmutation
  C) nuclear fussion
  D) nuclear fission
  Show Answer
  The correct answer is C .
• Question 2:

  In electrovalency, the oxidation number of the participating metal is always

  Options:
  A) decreasing
  B) increasing
  C) constant
  D) neutral
  Show Answer
  The correct answer is C .
• Question 3: Starch can be converted to ethyl alcohol by Options:
  A) distillation
  B) fermentation
  C) isomerization
  D) cracking
  E) cooking
  Show Answer
  The correct answer is B .
• Question 4: CO_g + H₂O_g $\to$ _2g + H_2g $\mathrm{\Delta }$H = -4100J. Which of the following factors favour the formation of hydrogen in the above reaction? i. high pressure. ii. low pressure iii. high temperature iv. use of excess steam Options:
  A) i, iii and iv
  B) iii only
  C) ii, iii and i
  D) iv only
  Show Answer
  The correct answer is D .
• Question 5: A piece of sea shell, when dropped into a dilute solution of hydrochloric acid, produces a colourless, odourless gas which turns clear limewater milky. The sea shell contains Options:
  A) sodium chloride
  B) ammonium nitrate
  C) calcium carbonate
  D) calcium chloride
  E) magnesium chloride
  Show Answer
  The correct answer is C .
• Question 6: CHCl₃ + Cl₂ → HCl + CCl₄. The reaction above is an example of? Options:
  A) an addition reaction
  B) a substitution reaction
  C) a chlorination reaction
  D) a condensation reaction
  Show Answer
  The correct answer is B .
• Question 7:

  What current in amperes will deposit 2.7g of aluminium in 2 hours?

  [Al = 27, F = 96 500 C mol^-1]

  Options:
  A) 32
  B) 8
  C) 4
  D) 16
  Show Answer
  The correct answer is C .
• Question 8: According to charles' law, the volume of a gas becomes zero at Options:
  A) 0 ^oC
  B) -100 ^oC
  C) -273 ^oC
  D) -373 ^oC
  Show Answer
  The correct answer is C .
• Question 9: The compounds CH₃CH₂CHO and CH₃COCH₃ can be distinguished from each other using Options:
  A) Dilute ammonia
  B) Benedict's solution
  C) Tollen's reagent
  D) Sodium hydroxide solution
  Show Answer
  The correct answer is C .
• Question 10: Oxygen is a mixture of two isotopes O and O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is? Options:
  A) 16.0
  B) 16.2
  C) 17.0
  D) 18.0
  Show Answer
  The correct answer is B .