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 401:

  Hydrogen diffused through a porous plug

  Options:
  A) thrice as fast as oxygen
  B) at the same speed as oxygen
  C) four times as fast as oxygen
  D) twice as fast as oxygen
  Show Answer
  The correct answer is C .
• Question 402: The tincture of iodine means iodine dissolved in Options:
  A) ethanol
  B) bromine chloride
  C) chlorine water
  D) water
  Show Answer
  The correct answer is A .
• Question 403: Which of the following types of bonding does not involve the formation of new substance? Options:
  A) Metallic
  B) covalent
  C) Co-ordinate
  D) Electrovalent
  Show Answer
  The correct answer is A .
• Question 404: Which of the following equilibria shows little or no net reaction when the volume of the system is decreased? Options:
  A) H_2(g) + I_2(g) ≈ 2HI_(g)
  B) 2NO₂^(g) ≈ N₂O_4(g)O_4(g)N₂O_4(g)
  C) PCI_5(g) ≈ PCI_3(g) + CI_2(g)
  D) ZnO_(s) + CO_2(g) ≈ ZnCO_3(g)
  Show Answer
  The correct answer is D .
• Question 405:

  What mass of K₂CrO₄ is required to prepare 250cm³ of 0.020 mol dm³ solution?

  [K₂CrO₄ = 194.2g mol^-1]

  Options:
  A) 0.97g
  B) 9.70g
  C) 19.42g
  D) 97.10g
  Show Answer
  The correct answer is A .
• Question 406: When chlorine Is passed into water and the resulting solution exposed to sunlight, the product formed are Options:
  A) Chlorine gas and hydrogen
  B) Oxygen and oxochlorate (I) acid
  C) Chlorine gas and oxochlorate (I) acid
  D) Hydrochloric acid and oxygen
  Show Answer
  The correct answer is D .
• Question 407: 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 408:

  

  In the diagram above, the curve that represents the production of oxgyen gas from the decomposition of KCIO₃ in the presence of MnO₂ catalyst is

  Options:
  A) R
  B) P
  C) S
  D) Q
  Show Answer
  The correct answer is B .
• Question 409: Which of the following decreases when a given mass of gas is compressed to half its initial volume? Options:
  A) Average intermolecular distance
  B) Frequency of collisions
  C) Number of molecules present
  D) Atomic radius of each particle
  Show Answer
  The correct answer is A .
• Question 410:

  2-methylprop-1-ene is a structuralisomer of?

  Options:
  A) But-1-yne
  B) 2-methyl But-1-ene
  C) 3-methyl prop-1-yne
  D) But-2-ene
  Show Answer
  The correct answer is D .