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 101: In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture? Options:
  A) Fractional distillation
  B) crystallization
  C) Filtration followed by evaporation
  D) Evaporation followed by sublimation
  E) Filtration followed by sublimation
  Show Answer
  The correct answer is D .
• Question 102: Which of the following classes of organic compounds undergoes rapid oxidation with bromine water? Options:
  A) alcohols
  B) alkenes
  C) carboxylic acids
  D) esters
  E) alkanes
  Show Answer
  The correct answer is B .
• Question 103: In the periodic table, the electrical and thermal conductivities are properties of elements that Options:
  A) decrease across the period and increase down the group
  B) increase across the period and decrease down the group
  C) decrease across the period and down the group`
  D) increase acrosss the period and down the group
  Show Answer
  The correct answer is A .
• Question 104: Under high pressure, real gases do not obey gas laws because their molecules? Options:
  A) have become more energetic
  B) have become less energetic
  C) have become smaller in size
  D) decompose into atoms
  E) start repelling each other
  Show Answer
  The correct answer is B .
• Question 105: The function of conc. H₂SO₄ in the esterification of ethanoic acid with ethanol is to Options:
  A) serve as a dehydrating agent
  B) serve as a solvent
  C) act as a catalyst
  D) prevent any side reaction
  E) serve as an oxidizing agent
  Show Answer
  The correct answer is C .
• Question 106:

  The situation obtained when a perfect gas expands into a vacuum is

  Options:
  A) ΔH is positive and TΔ S is zero
  B) ΔH is positive and T Δ S is negative
  C) ΔH is negative and TΔ S is zero
  D) ΔH is zero and T Δ S is positive
  Show Answer
  The correct answer is D .
• Question 107:

  220g of carbon dioxide contains ----- moles

  Options:
  A) 5
  B) 6
  C) 3
  D) 4
  Show Answer
  The correct answer is A .
• Question 108: The nucleus of the isotopes tritium contains Options:
  A) two neutrons with no protons
  B) one neutron and one proton
  C) two neutrons and one proton
  D) two neutrons, one proton and one electron
  Show Answer
  The correct answer is C .
• Question 109:

  

  It can be deduced that the rate of the reaction

  Options:
  A) for bath l is higher than path ll
  B) for path ll is higher than path l
  C) is the same for both paths at all temperatures
  D) depends on the values of both x and y at all pressures
  Show Answer
  The correct answer is B .
• Question 110:

  To obtain pure carbon(ii)oxide from its mixture with carbon(iv)oxide, the mixture should be?

  Options:
  A) Passed over heated copper(ii)oxide
  B) Bubbled through water
  C) Bubbled through conc H${}_2$SO${}_4$
  D) Bubbled through conc NAOH
  Show Answer
  The correct answer is D .