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 1611:

  Which of the following are mixtures?

  i. Petroleum
  ii. Rubber latex
  iii. Vulcanizer's solution
  iv. Carbon (II) sulphide

  Options:
  A) i, ii and iii
  B) i, ii and iv
  C) i and ii only
  D) i and iv
  Show Answer
  The correct answer is A .
• Question 1612:

  An element, X, forms a volatile hydride XH₃ with a vapour density of 17.0. The relative atomic mass of X is?

  (H = 1)

  Options:
  A) 34.0
  B) 31.0
  C) 20.0
  D) 14.0
  Show Answer
  The correct answer is B .
• Question 1613: 1.0 dm³ of distilled water was used to wash 2.0g of a precipitate of AgCl. If the solubility product of AgCl is 2.0 * 10^-10mol²dm^-6, what quantity of silver was lost in the process? Options:
  A) 2.029 * 10^-3mol dm^-3
  B) 1.414 * 10^-3mol dm^-3
  C) 2.029 * 10^-5mol dm^-3
  D) 1.414 * 10^-5mol dm^-3
  Show Answer
  The correct answer is D .
• Question 1614:

  2SO_2(g) + O_2(g) ↔ 2SO_3(g)

  ΔH = -189 kJ mol^-1

  The equilibrium constant for the reaction above is increased by

  Options:
  A) Increasing the temperature of the system
  B) Increase the pressure of the system
  C) The addition of a catalyst to the system
  D) Increasing the surface area of the vessel
  Show Answer
  The correct answer is B .
• Question 1615: The shape of ammonia molecules is Options:
  A) trigonal planar
  B) octahedral
  C) square planar
  D) tetrahedral
  Show Answer
  The correct answer is A .
• Question 1616: The function of zinc electrode in a galvanic cells is that it Options:
  A) undergoes reduction
  B) serves as the positive electrode
  C) production electons
  D) uses up electrons
  Show Answer
  The correct answer is C .
• Question 1617: A metal is extracted from its ore by the electrolysis of its molten chloride and it displaces lead from lead (ll) trioxonitrate (V) solution. The metal is Options:
  A) copper
  B) aluminium
  C) zinc
  D) sodium
  Show Answer
  The correct answer is D .
• Question 1618:

  The Consecutive members of an alkane homologous series differ by

  Options:
  A) CH
  B) CH${}_2$
  C) CH${}_3$
  D) C${}_n$H${}_n$
  Show Answer
  The correct answer is B .
• Question 1619: In a flame test for calcium, the flame appears Options:
  A) green when viewed through a blue glass
  B) blue when viewed through a blue glass
  C) orange -red when viewed through a blue glass
  D) brick-red when viewed through a blue-glass
  Show Answer
  The correct answer is D .
• Question 1620: The fuming of kettles is caused by the presence in the water of Options:
  A) calcium tetraoxosulphate (IV)
  B) calcium hydrogentrionocarbonate (IV)
  C) calcium hydroxide
  D) calcium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .