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 11:

  

  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 12: The reaction of an alkene with hydrogen in the presence of catalyst is Options:
  A) a substitution reaction
  B) an oxidation reaction
  C) a nucleophilic reaction
  D) an addition reaction
  Show Answer
  The correct answer is D .
• Question 13: If 24.4 g of lead (ll) trioxonitrate (V) were dissolved in 42 g of distilled water at 20^oC; calculate the solubility of the solute in gdm^-3. Options:
  A) 581.000.
  B) 0.581
  C) 5.810
  D) 58.100
  Show Answer
  The correct answer is A .
• Question 14: In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is - 57.3kJ. Therefore the heat of the reaction 2NaOH + H₂SO₄ $\to$ Na₂SO₄ + 2H₂O is Options:
  A) + 28.65 kJ
  B) - 28.65KJ
  C) + 57.3KJ
  D) - 114.6 KJ
  E) - 229.2 KJ
  Show Answer
  The correct answer is D .
• Question 15: A particle that contains a protons, 10 neutrons and 10 electrons is Options:
  A) positive ion
  B) neutral atom of a metal
  C) neutral atom of a non-metal
  D) negative ion
  Show Answer
  The correct answer is D .
• Question 16: The principle of column chromatography is based on the ability of the constituents to Options:
  A) move at different speeds in the column
  B) dissolve in each other in the column
  C) react with the solvent in the column
  D) react with each other in the column
  Show Answer
  The correct answer is A .
• Question 17: An element with atomic number twelve is likely to be Options:
  A) electrovalent with a velocity of 1
  B) electrovalent with a valency of 2
  C) covalent with a valency of 2
  D) covalent with valency of 4
  Show Answer
  The correct answer is B .
• Question 18: The raw materials used for the smelting of iron ore in a furnace is Options:
  A) CaSO₄
  B) CaCO₃
  C) CuSO₄
  D) Zn(NO₃)₂
  Show Answer
  The correct answer is B .
• Question 19:

  A compound contains 31.91% potassium, 28.93% chlorine and the rest oxygen. What is the chemical formula of the compound?

  [K = 39, Cl = 35.5, O = 16]

  Options:
  A) KClO₄
  B) KClO
  C) KClO₂
  D) KClO₃
  Show Answer
  The correct answer is D .
• Question 20: Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because Options:
  A) zinx is not rendered passive by acid
  B) hydrogen produced is oxidized to water
  C) oxides of nitrogen are produced
  D) all nitrates are soluble in water
  E) trioxonitrate(v)acid is a strong acid
  Show Answer
  The correct answer is E .