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 1871: Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises? Options:
  A) The bonds in the reacting molecules are more readily broken
  B) The molecular collisions become more violent
  C) A lower proportion of the molecules has the necessary minimum energy to react
  D) The collision frequency of the molecules increase
  Show Answer
  The correct answer is D .
• Question 1872: 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
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  The correct answer is B .
• Question 1873: Increasing the pressure of a gas Options:
  A) lowers the average kinetic energy of the molecules
  B) decreases the density of the gas
  C) decreases the temperature of the gas
  D) increases the density of the gas
  E) increases the volume of the gas
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  The correct answer is D .
• Question 1874: The acid in electrolysis of water is dilute Options:
  A) HNO₃
  B) CH₃COOH
  C) H₂SO
  D) HCl
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  The correct answer is C .
• Question 1875:

  

  The diagram above represents the formation of

  Options:
  A) a metallic bond
  B) an electrovalent bond
  C) a covalent bond
  D) a coordinate covalent bond
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  The correct answer is C .
• Question 1876: In which of the following are the aqueous solutions of each of the substances correctly arranged in order to decreasing acidity? Options:
  A) Ethanoic acid, milk or magnesia, sodium chloride, hydrochloric acid and sodium hydroxide
  B) Ethanoic acid, hydrochloric acid, milk of magnesia, sodium chloride and sodium chloride and sodium hydroxide
  C) Hydrochloride acid, ethanol acid, sodium chloride, milk of magnesia and sodium hydroxide
  D) Hydrochloride acid, sodium hydroxide sodium chloride, ethanol acid, and milk of magnesia
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  The correct answer is C .
• Question 1877: The formula CH₂ for ethanoic acid is regarded as its Options:
  A) Molecular formula
  B) General formula
  C) Empirical formula
  D) Structural formula
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  The correct answer is C .
• Question 1878: The residual solids from the fractional distillation of petroleum are used as Options:
  A) coatings of pipes
  B) raw materials for the cracking process
  C) fuel for the driving tractors
  D) fuel for jet engines
  Show Answer
  The correct answer is A .
• Question 1879: When a few drops of water is added to a blue anhydrous cobalt (II) chloride, the colour changes to Options:
  A) white
  B) pink
  C) red
  D) blue
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  The correct answer is B .
• Question 1880: When ΔH is negative, a reaction is said to be Options:
  A) ionic
  B) reversible
  C) exothermic
  D) endothermic
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  The correct answer is C .