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 141: The number of electronic shells contained in an atom with electron configuration 1s²2s²2p⁶3s²3p⁶4s² is Options:
  A) 3
  B) 2
  C) 4
  D) 5
  Show Answer
  The correct answer is C .
• Question 142:

  Hydrocarbons which will react with Tollen's reagent conform to the general formula

  Options:
  A) C${}_n$H${}_{2n}$
  B) C${}_n$H${}_{2n+2}$
  C) C${}_n$H${}_{2n-2}$
  D) C${}_n$H${}_{2n+1}$OH
  Show Answer
  The correct answer is C .
• Question 143:

  An element used in the production of matches is

  Options:
  A) nitrogen
  B) aluminium
  C) copper
  D) sulphur
  Show Answer
  The correct answer is D .
• Question 144: Which of the following statement is true of the electrochemical series? Options:
  A) Electropositivity of metals increase down the series
  B) Electropositivity of non-metals decrease down the series
  C) Electronegativity of non-metals decrease down the series
  D) Electropositivity of metals decreases down the series
  Show Answer
  The correct answer is D .
• Question 145: In an equilibrium reaction, which of the following conditions indicates that maximum yield of the product will be obtained? Options:
  A) Equilibrium constant is very large
  B) ∆H - T∆S = O
  C) ∆ H > T ∆ S
  D) Equilibrium constant is less than zero
  Show Answer
  The correct answer is A .
• Question 146:

  The lanthanides and actinides are located in which block of the periodic table?

  Options:
  A) P-block
  B) S-block
  C) F-block
  D) D-block
  Show Answer
  The correct answer is C .
• Question 147: Which of the following allotrope of carbon is a constituent of a lead pencil? Options:
  A) Graphite
  B) Diamond
  C) Lampblack
  D) Soot
  Show Answer
  The correct answer is A .
• Question 148:

  Zn_(s) + CuSO_4(aq) $\to$ ZnSO_4(aq) + Cu_(s)

  In the reaction above, the oxidizing agent is

  Options:
  A) CuSO_4(aq)
  B) ZnSO_4(aq)
  C) Cu_(s)
  D) Zn_(s)
  Show Answer
  The correct answer is A .
• Question 149:

  A compound contains 40.0% carbon 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, find the molecular formula.

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

  Options:
  A) CH₂O
  B) C₃H₆O₃
  C) C₆H₁₂O₆
  D) C₆H₁₂O₃
  Show Answer
  The correct answer is C .
• Question 150:

  In order to electroplate spoon with silver, the arrangement of the electrolytic cell is?

  Options:
  A) the anode is a silver rod and the cathode is the spoon
  B) the anode is the spoon and the cathode is a silver rod
  C) the electrolyte is silver trioxonitrate(v)( solution and the cathode is a silver rod.
  D) the electrolyte is silver trioxonitrate(v) solution and the anode is the spoon
  Show Answer
  The correct answer is A .