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 451:

  Which one of the following is not a mixture?

  Options:
  A) Air
  B) Mercury
  C) Milk
  D) Cement
  Show Answer
  The correct answer is B .
• Question 452:

  What is the sum of the oxidation numbers in a neutral compound?

  Options:
  A) +2
  B) -1
  C) 0
  D) +1
  Show Answer
  The correct answer is C .
• Question 453: In the industrial production of H₂ is removed by (solution) Options:
  A) washing under pressure
  B) drying over phosphorus (V) oxide
  C) passing the mixture to the limewater
  D) using ammonical copper (I) chlorine
  Show Answer
  The correct answer is A .
• Question 454: How many faraday of electricity is required to produce 0.25 mole of copper? Options:
  A) 1.00F
  B) 0.01F
  C) 0.05F
  D) 0.50F
  Show Answer
  The correct answer is D .
• Question 455:

  SO${}_2$ + O${}_2$ 2SO${}_3$

  In the reaction above, the most suitable catalyst is?

  Options:
  A) chromium(vi)oxide
  B) iron(iii)oxide
  C) copper(i)oxide
  D) vanadium(v)oxide
  Show Answer
  The correct answer is D .
• Question 456: The dissolution of common salt in water is a physical change because Options:
  A) the salt can be obtained by crystallization
  B) the salt can be recovered by the evaporation of water
  C) heat is not generated during mixing
  D) the solution will not boil at 100^oC
  Show Answer
  The correct answer is C .
• Question 457: 0.07g of a hydride of carbon occupies 56.0cm³ at S.T.P. when vaporized and contains 14.29% by mass of hydrocarbon is(C = 12, H = 1) Options:
  A) CH₄
  B) C₂H₂
  C) C₂H₄
  D) C₂H₆
  E) C₃H₈
  Show Answer
  The correct answer is C .
• Question 458: Which of the following compounds can be represented by the molecular formula C₂H₆O? Options:
  A) Propanel
  B) Ethanol
  C) Methanoic acid
  D) Glucose
  Show Answer
  The correct answer is B .
• Question 459:

  At S. T. P how many litres of hydrogen can be obtained from the reaction of 500 cm³ of 0.5 M H ₂SO ₄ with excess zinc metal?

  (Gram molecular volume of H₂ = 22. 4 dm ³)

  Options:
  A) 22.4 dm ³
  B) 11 . 2 dm ³
  C) 6. 5 dm ³
  D) 5. 6 dm ³
  E) 0. 00 dm ³
  Show Answer
  The correct answer is D .
• Question 460: What is the valence shell electron configuration of the element with atomic number 17? Options:
  A) 1s² 2s² 2p⁶ 3s² 3p⁴
  B) 1s² 2s² 2p⁶ 3s² 3p⁵
  C) 2s² 2p⁶
  D) 3s² 3p⁵
  Show Answer
  The correct answer is B .