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 1641:

  

  The data in the table above shows the rate of reaction of nitrogen (ll) oxide with chlorine at 25^oC It can be concluded that doubling the initial concentration of NO increase the rate of reaction by a factor of

  Options:
  A) two
  B) three
  C) four
  D) five
  Show Answer
  The correct answer is C .
• Question 1642:

  Helium is used in observation of ballons because it is?

  Options:
  A) Light and combustible
  B) light and non-combustible
  C) heavy and combustible
  D) heavy and non-combustible
  Show Answer
  The correct answer is B .
• Question 1643: In the laboratory preparation of ammonia, the flask is placed in a slanting position so as to Options:
  A) prevent condensed water from breaking the reaction flask
  B) enable the proper mixing of the reactions in the flask
  C) enhance the speed of the reaction
  D) prevent formation of precipitate
  Show Answer
  The correct answer is A .
• Question 1644:

  Which of the following gases will diffuse fastest when passed through a porous plug?

  [H = 1, C = 12, N = 14, O = 16]

  Options:
  A) Propane
  B) Oxygen
  C) Methane
  D) Ammonia
  Show Answer
  The correct answer is C .
• Question 1645: An element wil readily form an electrovalent compound if it electron configuration is Options:
  A) 2, 8, 1
  B) 2, 8, 4
  C) 2, 8, 8
  D) 2, 8, 5
  Show Answer
  The correct answer is A .
• Question 1646: The gas responsible for most of the fatal explosions in coal mines is Options:
  A) butane
  B) ethene
  C) ethane
  D) methane
  Show Answer
  The correct answer is D .
• Question 1647:

  Which of the following alkanes has a straight-chain structure?

  Options:
  A) Cyclopentane (C5H10)
  B) Isobutane (C4H10)
  C) 2 - methyl propane (C4H10)
  D) Pentane (C5H12)
  Show Answer
  The correct answer is D .
• Question 1648: In the reaction of oxygen with hydrogen to produce water, which of the following statements is true? Options:
  A) One atom of hydrogen reacts with two atoms of oxygen to give one molecule of water
  B) Two atoms of hydrogen react with two atoms of oxygen to give two molecules of water
  C) One molecule of oxygen reacts with one molecule of hydrogen to give two molecules of water
  D) One molecule of hydrogen reaccts with two molecules of oxygen to give three molecules of water
  E) One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water
  Show Answer
  The correct answer is E .
• Question 1649:

  

  Use the diagram above to answer this question.

  Which of the following structural formula is NOT isomeric with the others?

  Options:
  A) A
  B) B
  C) C
  D) D
  E) E
  Show Answer
  The correct answer is D .
• Question 1650:

  The emission of two successive beta particles from the nucleus ${}_{15}^{32}P$ will produce

  Options:
  A) ${}_{14}^{30}$Si
  B) ${}_{13}^{32}$Al
  C) ${}_{17}^{32}$Cl
  D) ${}_{16}^{32}$S
  Show Answer
  The correct answer is C .