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 751: Temporary hard water is formed when rain water containing dissolved carbon(IV) oxide flows over deposits of Options:
  A) CaCO₃
  B) Na₂CO₃
  C) Na₂SO₄
  D) CaSO₄
  Show Answer
  The correct answer is A .
• Question 752:

  The shape of ammonia molecule is?

  Options:
  A) Trigonal planar
  B) Octahedral
  C) Square planar
  D) Tetrahedral
  Show Answer
  The correct answer is A .
• Question 753:

  Zn + H₂ SO₄ → ZnSO₄ + H₂

  In the above reaction how much Zinc will be left of 1.0 M of H₂SO?

  [Zn =65, s = 32, O = 16, H = 1]

  Options:
  A) 1.35g
  B) 1.00g
  C) 0.70g
  D) 0.65g
  E) 0.00g
  Show Answer
  The correct answer is A .
• Question 754:

  

  If in the graph above 1 dm³ of a saturated solution of KCL is cooled from 80^oC, the mass of crystals deposited will be  [K = 39, Cl = 35.5]

  Options:
  A) 7.45 g
  B) 14.90 g
  C) 74.50 g
  D) 149.00 g
  Show Answer
  The correct answer is D .
• Question 755: Which of the following gases can be collected by the upward displacement of air? Options:
  A) NO
  B) H ₂
  C) NH₃
  D) Cl ₂
  Show Answer
  The correct answer is D .
• Question 756:

  A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

  Options:
  A) collisions are perfectly elastic
  B) forces of repulsion exist
  C) forces of repulsion and attraction are in equilibrium
  D) collisions are inelastic
  Show Answer
  The correct answer is B .
• Question 757: The radioisotope used in industrial radiography for the rapid checking of faults in welds and casting is Options:
  A) Phosphorus-32
  B) Cobalt-60
  C) Carbon-14
  D) Iodine-131
  Show Answer
  The correct answer is B .
• Question 758:

  An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is

  Options:
  A) Zn
  B) Ca
  C) Al
  D) Po
  Show Answer
  The correct answer is A .
• Question 759: The salt formed from a reaction between citric acid and sodium hydroxide in solution will be Options:
  A) acidic
  B) basic
  C) complex
  D) neutral
  Show Answer
  The correct answer is B .
• Question 760:

  The nucleus of an atom consists of?

  Options:
  A) Electrons and neutrons
  B) Electrons and protons
  C) Protons and neutrons
  D) None of the above
  Show Answer
  The correct answer is C .