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 1661: In the reaction 1O^-₃ + 5l^- + 6H⁺ → 31₂ + 3H₂O, the oxidizing agent is? Options:
  A) H⁺
  B) l^-
  C) 1O^-
  D) l₂
  Show Answer
  The correct answer is C .
• Question 1662: Which of the following is NOT true of metals? Options:
  A) They are good conductors of electricity
  B) They ionize by electron loss
  C) Their oxides are acidic
  D) They have high melting points
  Show Answer
  The correct answer is C .
• Question 1663: Starch can be converted to ethyl alcohol by Options:
  A) distillation
  B) fermentation
  C) isomerization
  D) cracking
  E) cooking
  Show Answer
  The correct answer is B .
• Question 1664:

  

  The ∆H for the reaction represented by the energy profile above is

  Options:
  A) -100 kJ mol-^-1
  B) + 100 kJ mol^-1
  C) +50 kJ mol^-1
  D) -50 kJ mol^-1
  Show Answer
  The correct answer is D .
• Question 1665:

  Sodium reacts vigorously with water to produce

  Options:
  A) Sodium chloride (NaCl) and oxygen gas (O2)
  B) Sodium nitrate (NaNO3) and water (H2O)
  C) Sodium hydroxide (NaOH) and hydrogen gas (H2)
  D) Sodium oxide (Na2O) and hydrogen gas (H2)
  Show Answer
  The correct answer is C .
• Question 1666:

  

  The set-up above would be useful for determining the amount of

  Options:
  A) oxygen in air
  B) water vapour in air
  C) CO₂ in air
  D) arygen in air
  Show Answer
  The correct answer is B .
• Question 1667:

  A solution contains 20g of solute in 180g of solvent. If the solvent is water, what is the concentration of the solution in terms of mass by mass percentage

  Options:
  A) 11.%
  B) 22.2%
  C) 10%
  D) 20%
  Show Answer
  The correct answer is C .
• Question 1668: The general formula of an alkyl halide (where X represents the halide) is? Options:
  A) C_nH_2n2X
  B) C_nH_2n + ₁X
  C) C_nH_2n + ₂X
  D) C_nH_2nX
  Show Answer
  The correct answer is B .
• Question 1669:

  

  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 1670: A reaction takes places spontaneously if?
  Options:
  A) ∆G = O
  B) ∆S < O and ∆H > O
  C) ∆H < T ∆S
  D) ∆G > O
  Show Answer
  The correct answer is C .