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 51: which of the following polymers is suitable for packaging and electrical insulation? Options:
  A) polyamide
  B) polyethene
  C) polycarbonate
  D) polystyrene
  Show Answer
  The correct answer is D .
• Question 52: Given that M is the mass of substance deposited in an electrolysis and Q the quantity of electricity consumed, then Faraday's law can be written as Options:
  A) M = Z/Q
  B) M = Q/Z
  C) M = Z/2Q
  D) M = QZ
  Show Answer
  The correct answer is D .
• Question 53:

  

  The IUPAC name for the compound is

  Options:
  A) 2,3-dimethylpent-2,3-ene
  B) 2, 3- dimethylpent-2-ene
  C) 3, 4-dimethylpent-3-ene
  D) 3,4-dimethylpentene
  E) 3,4-dimethlhept-2-ene
  Show Answer
  The correct answer is B .
• Question 54: During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?(M = 65, If = 96,500 C per mole of electron) Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 55:

  CH₂S_(g) + O_2(g) → 2Cn + SO_2(g)

  What is the change in the oxidation number of copper in the reaction?

  Options:
  A) 0 to + 2
  B) 0 to + 1
  C) C + 1 to 0
  D) + 2 to + 1
  Show Answer
  The correct answer is C .
• Question 56:

  

  The IUPAC nomenclature for the structure above is

  Options:
  A) 2, 3 - dichloro - 4, 4, 5 - trimethyl pent - 2 - ene
  B) 4, 5 - dichloro - 2, 3 - dimethyl hex - 2 - ene
  C) 2, 3 - dichloro - 4, 4 - dimethyl hex - 2- ene
  D) 2, 3 dichloro - 2, 2 - dimethyl hex - 2 - ene
  Show Answer
  The correct answer is C .
• Question 57: Pure solvents are obtained by Options:
  A) Distillation
  B) Condensation
  C) Extraction
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 58: Sulphur Options:
  A) forms two alkaline oxides
  B) is spontaneously flammable
  C) burns with a blue flame
  D) conducts electricity in the molten state
  E) is usually stored in the form of sicks in water
  Show Answer
  The correct answer is C .
• Question 59: An effect of thermal pollution on water bodies is that the Options:
  A) volume of water reduces
  B) volume of chemical waste increase
  C) level of oxides of nitrogen increase
  D) level of oxygen reduces
  Show Answer
  The correct answer is D .
• Question 60: Three drops of a 1.0 mol dm^-3 solution of HCl was added to 20 cm³ of a solution of pH6.4. The pH of the resulting solution will be Options:
  A) close to that of pure water
  B) less than 6.4
  C) greater than 6.4
  D) unaltered
  Show Answer
  The correct answer is B .