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 151: A heterogenous mixture can be defined as any mixture Options:
  A) of a solute nd a solvent
  B) whose cmposition is uniform
  C) whose composition is not uniform
  D) formed by solids and liquids
  Show Answer
  The correct answer is C .
• Question 152: Vulcanization of rubber is a process by which Options:
  A) isoprene units are joined to produce rubber
  B) rubber latex is coagulated
  C) sulphur is chemically combined in the rubber
  D) water is removed from the rubber
  Show Answer
  The correct answer is C .
• Question 153: Which of the following substances is a mixture? Options:
  A) granulated sugar
  B) sea water
  C) sodium chloride
  D) Iron fillings
  Show Answer
  The correct answer is B .
• Question 154:

  The reaction $2H_{2}S+S{O}_2\to 3S+2H_{2}O$ is

  Options:
  A) not a redox reaction because there is no oxidant in the reaction
  B) not a redox reaction because there is no reductant in the reaction
  C) a redox reaction in which H${}_2$S is the oxidant and SO${}_2$ is the reductant
  D) a redox reaction in which SO${}_2$ is the oxidant and H${}_2$S is the reductant
  Show Answer
  The correct answer is D .
• Question 155:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 156: A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be Options:
  A) sulphur (VI) oxide
  B) hydrogen chloride
  C) sulphur (VI) oxide
  D) hydrogen sulphide
  Show Answer
  The correct answer is D .
• Question 157: Hydrogen is used in oxy-hydrogen flames for melting metals because it Options:
  A) evolves a lot of heat when burnt
  B) combines explosively with oxygen
  C) is a very light gas
  D) is a rocket fuel
  Show Answer
  The correct answer is A .
• Question 158: The rate of diffusion of a gas Y is twice that of Z If the relative molecular mass of Y is 64 and the two gases diffuse under the same conditions, find the relative molecular mass of Z Options:
  A) 32
  B) 4
  C) 8
  D) 16
  Show Answer
  The correct answer is D .
• Question 159:

  What is the main source of carbon monoxide (CO) in urban areas?

  Options:
  A) Volcanic eruptions
  B) Vehicle emissions
  C) Forest fires
  D) Industrial processes
  Show Answer
  The correct answer is B .
• Question 160: P1V1 = P2V2 supports ? Options:
  A) Charles’s law
  B) Boyles’s law
  C) Graham’s law
  D) Avogadro’s law
  Show Answer
  The correct answer is B .