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 881: A mixture of sand, ammonium chloride and sodium chloride is best separated by? Options:
  A) sublimation followed by addition of water and filteration
  B) sublimation followed by addition of water and evaporation
  C) addition of water followed by filtration and sublimation
  D) addition of water followed by crystallization and sublimation
  Show Answer
  The correct answer is A .
• Question 882: The gas that can best be collected by downward displacement of air is Options:
  A) Chlorine
  B) Sulphur (IV) oxide
  C) Ammonia
  D) Carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 883:

  A sample of any of the following substances disappearsafter some time when exposed to air like camphor, naphthalene, or dry ice. This phenomenon is called?

  Options:
  A) Sublimation
  B) Evaporation
  C) Diffusion
  D) Radiation
  Show Answer
  The correct answer is A .
• Question 884: The shape of s-orbitals is Options:
  A) spherical
  B) elliptical
  C) spiral
  D) circular
  Show Answer
  The correct answer is A .
• Question 885:

  Hydrogen bond is a sort of

  Options:
  A) van der waals force
  B) dative bond
  C) ionic bond
  D) a covalent bond
  Show Answer
  The correct answer is D .
• Question 886: What is the IUPAC nomenclature of the compound NaCIO? Options:
  A) sodium oxochlorate (I)
  B) sodium chloro (I) oxide
  C) sodium monooxochlorate (II)
  D) sodium chloro (I) monoxide
  Show Answer
  The correct answer is A .
• Question 887: A mixture is different from a compound because Options:
  A) the properties of a compound are those of its individual constituents while those of a mixture differ from its constituents
  B) a mixture is always homogeneous while a compound is not
  C) the constituent of a compound are chemically bound together while those of a mixture are not
  D) a mixture can be represented by a chemical formula while a compound cannot
  Show Answer
  The correct answer is C .
• Question 888:

  MnO₂ + 2CI^- + 4H⁺ → MnO²⁺ + CI₂ + 2H₂O.

  The changes is oxidation numbers when the manganese, chloride and hydrogen ions react according to the above equation are respectively?

  Options:
  A) 2, 2, 4
  B) -1, -2, 4
  C) -2, 1, 0
  D) 2, 4, 0
  Show Answer
  The correct answer is C .
• Question 889: The air around a petroleum refinery is most likely to contain? Options:
  A) CO₂, SO₃ and N₂O
  B) CO₂, CO and N₂O
  C) SO₂, CO and NO₂
  D) PH₃ H₂O and CO₂
  Show Answer
  The correct answer is C .
• Question 890: What are the values of x, y and z respectively in the equation: xCu + yHNO₃ → xCu(NO₃)₂ + 4H₂O + zNO? Options:
  A) 4: 1: 2
  B) 3:8:2
  C) 2:8:3
  D) 8:3:2
  Show Answer
  The correct answer is B .