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 871:

  A certain hydrocarbon on complete combustion at s.t.p produced 89.6dm${}^3$ of CO${}_2$ and 54g of water. The hydrocarbon should be

  Options:
  A) C${}_6$H${}_6$
  B) C${}_4$H${}_{10}$
  C) C${}_5$H${}_{10}$
  D) C${}_4$H${}_6$
  Show Answer
  The correct answer is D .
• Question 872: Alkaonic acids have low volatility compared with alkanols because they? Options:
  A) are more polar than alkaonls
  B) have two oxygen atoms while alkanols have one
  C) form hydrogen bonds while alkanols do not
  D) form two hydrogen bonds while alkanols form one
  Show Answer
  The correct answer is D .
• Question 873: The oxidation number of boron in NaBH ₄ is Options:
  A) -3
  B) -1
  C) +1
  D) +3
  Show Answer
  The correct answer is D .
• Question 874: When stem is passed over red hot carbon the substances produced are Options:
  A) hydrogen and trioxocarbonate (IV) acid
  B) hydrogen, oxygen and carbon (IV) oxide
  C) hydrogen and carbon (ii) oxide
  D) hydrogen and carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 875: A major process involved in the softening of hard water is the? Options:
  A) conversation of a soluble calcium salt to its trioxoncarbonate (lV)
  B) decomposition of calcium rioxocarbonate (lV)
  C) conversion of an insoluble calcium salts to its trioxocarbonate (lV)
  D) oxidation of calcium atoms to its ions
  Show Answer
  The correct answer is A .
• Question 876: Ammonium chloride can be separated from its mixture with common salt by Options:
  A) Distillation
  B) Evaporation
  C) Decantation
  D) Sublimation
  Show Answer
  The correct answer is D .
• Question 877:

  What is the principal ore of iron, from which iron is extracted?

  Options:
  A) Calcite
  B) Bauxite
  C) Magnetite
  D) Hematite
  Show Answer
  The correct answer is D .
• Question 878:

  Zn + H₂ SO₄ → ZnSO₄ + H₂

  In the above reaction how much Zinc will be left of 1.0 M of H₂SO?

  [Zn =65, s = 32, O = 16, H = 1]

  Options:
  A) 1.35g
  B) 1.00g
  C) 0.70g
  D) 0.65g
  E) 0.00g
  Show Answer
  The correct answer is A .
• Question 879:

  A chemical process in which there is a gain of electrons is known as?

  Options:
  A) Sublimation
  B) Reduction
  C) Oxidation
  D) Distillation
  Show Answer
  The correct answer is B .
• Question 880: A piece of burning sulphur will continue to burn in a gas jar of oxygen to give misty fumes which readily dissolved in water. The resulting liquid is Options:
  A) sulphur (VI) trioxide
  B) tetraoxosulphate (VI) acid
  C) trioxosulphate (IV) acid
  D) dioxosulphate (II) acid
  E) hydrogen sulphide
  Show Answer
  The correct answer is C .