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 631: Which of the following is a physical change? Options:
  A) The bubbling of chlorine into water
  B) The bubbling of chlorine into a jar contanining hydrogen
  C) The dissolution of sodium chloride in water
  D) The passing of steam over heated iron
  Show Answer
  The correct answer is C .
• Question 632:

  The molecular shape and bond angle of water are respectively

  Options:
  A) linear, 180°
  B) bent, 109.5°
  C) tetrahedral, 109.5°
  D) bent, 105°
  Show Answer
  The correct answer is D .
• Question 633: The atomic number of caesium is 55 and its atomic mass is 133. The nucleus of caesium atom therefore contains Options:
  A) 78 protons and 55 elections
  B) 55 protons and 78 neutrons
  C) 55 neutrons 78 electrons
  D) 78 protons and 55 neutrons
  Show Answer
  The correct answer is B .
• Question 634: Pick out the correct statement Options:
  A) Zin heated to redness reacts with steam to give oxygen and zinc oxide
  B) Zinc heated to redness reacts with steam to give oxygen and hydrogen
  C) Zinc does not react with hot or cold water
  D) Zinc reacts with hot water to form zinc oxide and hydrogen
  E) Zinc reacts very easily with cold water to give zinc oxide and hydrogen
  Show Answer
  The correct answer is D .
• Question 635: An example of an acidic oxide is Options:
  A) NO
  B) CO
  C) SO₂
  D) CuO
  Show Answer
  The correct answer is C .
• Question 636:

  H${}^{+}$ + OH${}^{-}$ H${}_2$O

  The equation above illustrates

  Options:
  A) precipitation
  B) hydration
  C) hydrolysis
  D) neutralization
  Show Answer
  The correct answer is D .
• Question 637: Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore, Options:
  A) P will form an electrovalent bond with R
  B) Q will form a covalent bond with S
  C) R will form an electrovalent bond with S
  D) Q will form an electrovalent bond with S
  E) Q will form a covalent bond with R
  Show Answer
  The correct answer is D .
• Question 638:

  

  The IUPAC nomenclature of the organic compound with the above structural formula is

  Options:
  A) 3-ethyl-2,5-dimethylhexane
  B) 4-ethyl-2,5-dimethylhexane
  C) 3-ethyl-2,5,5 - trimethylpentane
  D) 3-ethyl, 1,1,4-trimethylpentane
  Show Answer
  The correct answer is A .
• Question 639:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 640: Which of the following is a measure of the average kinetic energy of the molecules of a substance? Options:
  A) Volume
  B) Mass
  C) Pressure
  D) Temperature
  Show Answer
  The correct answer is D .