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 51: How many coulombs of electricity are passed through a solution in which 6.5 amperes are allowed to run for 1.0 hour? Options:
  A) 3.90 x 10² coulombs
  B) 5.50 x 10³ coulombs
  C) 6.54 x 10³ coulombs
  D) 2.34 x 10⁴ coulombs
  Show Answer
  The correct answer is D .
• Question 52:

  When chlorine water is exposed to bright sunlight, the following products are formed

  Options:
  A) HCl${}_{(aq)}$ and Cl${}_2$
  B) HOCl${}_{(aq)}$ and Cl${}_2$
  C) HCl${}_{(aq)}$ and O${}_2$
  D) HOCl${}_{(aq)}$ and O${}_2$
  Show Answer
  The correct answer is C .
• Question 53:

  (1/2)Zn²⁺_(aq) + e^- → (1/2) Zn_(s)

  In the reaction above, calculate the quantity of electricity required to discharge zinc.

  [F = 96 500 C mol^-1]

  Options:
  A) 0.965 * 10₄C
  B) 4.820 * 10₄C
  C) 9.650 * 10₄C
  D) 48.200 * 10₄C
  Show Answer
  The correct answer is C .
• Question 54:

  Why is water often referred to as the "universal solvent"?

  Options:
  A) Water is the most abundant substance on Earth
  B) Water is essential for all living organisms.
  C) Water is involved in many chemical reactions
  D) Water can dissolve a wide variety of substances due to its polar nature
  Show Answer
  The correct answer is D .
• Question 55: Calcium hydroxide is added in the treatment of town water supply to Options:
  A) kill bacteria in the water
  B) facilitate coagulation of organic particles
  C) facilitate sedimentation
  D) improve the taste of the water
  Show Answer
  The correct answer is B .
• Question 56: Vulcanization involves the removal of Options:
  A) A monomer
  B) The single bond
  C) The double bond
  D) A polymer
  Show Answer
  The correct answer is C .
• Question 57: Which of the following happens during the electrolysis of molten sodium chloride? Options:
  A) Sodium ion loses an electron
  B) Chlorine atom gains an electron
  C) Chlorine ion gains an electron
  D) Sodium ion is oxidized
  E) Chloride ion is oxidized
  Show Answer
  The correct answer is E .
• Question 58:

  If the volume of a given mass of a gas at 0ºc is29.5cm${}^3$. What will be the volume of the gas at 15ºc, given that the pressure remains constant.

  Options:
  A) 31.6
  B) 62.2
  C) 32.7
  D) 31.1
  Show Answer
  The correct answer is D .
• Question 59: The bleaching action of chlorine gas is effective due to the presence of Options:
  A) hydrogen chloride
  B) water
  C) air
  D) oxygen
  Show Answer
  The correct answer is B .
• Question 60:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
  Show Answer
  The correct answer is B .