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 61: When a few drops of water is added to a blue anhydrous cobalt (II) chloride, the colour changes to Options:
  A) white
  B) pink
  C) red
  D) blue
  Show Answer
  The correct answer is B .
• Question 62: A common characteristic between zinc and the other transition elements is the ability to Options:
  A) have variable oxidation states
  B) from complex ions
  C) act as a catalyst
  D) from coloured ions
  Show Answer
  The correct answer is B .
• Question 63:

  

  In the electrolysis of aqueous solution of K₂SO ₄ in the above cell, which species migrate to the anode?

  Options:
  A) SO^2-OH ^-
  B) K ⁺ and SO ₄^2-
  C) OH and HO
  D) H₃O ⁺ and K
  Show Answer
  The correct answer is A .
• Question 64: A particle that contains 9 protons, 10 neutrons and 10 electrons is a Options:
  A) negative ion
  B) positive ion
  C) neutral atom of non-metal
  D) neutral atom of a metal
  Show Answer
  The correct answer is A .
• Question 65:

  In the reaction:

  M + N → P

  ΔH = +Q kJWhich of the following would increase the concentration of the product?

  Options:
  A) Adding a suitable catalyst
  B) Increasing the concentration of P
  C) Increasing the temperature
  D) Decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 66: In the manufacture of iron in the blast furnace, iron (lll) oxide is mixed with coke and limestone, and different reactions occur in the process. Which of the following statements is true with respect to these reactions? Options:
  A) the coke is a powerful reducing agent and easily converts the iron oxide to iron
  B) the calcuim carbonate reacts with SiO₂ an earthly impurity in the ore, to from calcuim silicate
  C) the coke will react with the iron produced to form steel
  D) all the carbondioxide required in the process comes from the decomposition of the calcium carbonate
  E) the calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity
  Show Answer
  The correct answer is E .
• Question 67: The property used in obtaining oxygen and nitrogen industrially from air is the? Options:
  A) boiling point
  B) density
  C) rate of diffusion
  D) solubility
  Show Answer
  The correct answer is A .
• Question 68:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 69:

  The cost of discharging 6.0g of a divalent metal, X from its salt is ₦12.00. What is the cost of discharging 9.0g of a trivalent metal, Y from its salt under the same condition?

  [X = 63, Y = 27, 1F = 96,500C]

  Options:
  A) N12.00
  B) N27.00
  C) N63.00
  D) N95.00
  Show Answer
  The correct answer is C .
• Question 70:

  

  The I.U.P.A.C name for the compound

  Options:
  A) 2-methyl-3-pentene
  B) 4-methyl-2-pentane
  C) 2-methyl-2-pentene
  D) 4-methylpent-2-ene
  E) 2-methyl-3-pentane
  Show Answer
  The correct answer is D .