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 131:

  A sample of any of the following substances disappearsafter some time when exposed to air like camphor, naphthalene, or dry ice. This phenomenon is called?

  Options:
  A) Sublimation
  B) Evaporation
  C) Diffusion
  D) Radiation
  Show Answer
  The correct answer is A .
• Question 132: The type of iron that is best suited for welding, making nails, chains and iron rods is Options:
  A) pig iron
  B) wrought iron
  C) cast iron
  D) iron pyrites
  Show Answer
  The correct answer is B .
• Question 133:

  0.1 faraday of electricity deposited 2.95 g of nickel during electrolysis of an aqueous solution.

  Calculate the number of moles of nickel that will be deposited by 0.4 faraday? (Ni = 58.7)

  Options:
  A) 0.20
  B) 0.30
  C) 0.04
  D) 5.87
  Show Answer
  The correct answer is A .
• Question 134:

  

  In the graph above, the activation energy of the catalyzed reaction is

  Options:
  A) 100KJ
  B) 300KJ
  C) 250KJ
  D) 200KJ
  Show Answer
  The correct answer is A .
• Question 135: The enzymes responsible for converting sucrose into two simple isomeric sugars is Options:
  A) maltase
  B) amylase
  C) invertase
  D) lactase
  Show Answer
  The correct answer is C .
• Question 136:

  The metal used to recover copper from a solution of copper sulphateis?

  Options:
  A) Na
  B) Ag
  C) Hg
  D) Fe
  Show Answer
  The correct answer is D .
• Question 137:

  What is the atomic number of aluminium?

  Options:
  A) 13
  B) 26
  C) 14
  D) 12
  Show Answer
  The correct answer is A .
• Question 138: The solubility product of Cu(IO₃)₂ is 1.08 * 10^-7. Assuming that neither ions react appreciable with water to form H⁺ and OH^-, what is the solubility of this salt? Options:
  A) 2.7 * 10^-8 mol dm^-3
  B) 9.0 * 10^-8 mol dm^-3
  C) 3.0 * 10^-3 mol dm^-3
  D) 9.0 * 10^-3 mol dm^-3
  Show Answer
  The correct answer is D .
• Question 139:

  Suitable reagents for the laboratory preparation nitrogen are

  Options:
  A) sodium dioxonitrate(III) and ammonium chloride
  B) sodium trioxonitrate(V) and ammonium chloride
  C) sodium chloride and ammonium trioxonitrate(V)
  D) sodium chloride and ammonium di-ozonitrate(III)
  Show Answer
  The correct answer is A .
• Question 140:

  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 .