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 481:

  One of the following is not a physical property of monosaccharides?

  Options:
  A) Monosaccharides get charred when heated
  B) Monosaccharides are water-soluble, sweet substances
  C) They are highly vital to the exploration of metals
  D) They can be reduced to sugar alcohols
  Show Answer
  The correct answer is C .
• Question 482: Which of the following equilibria shows little or no net reaction when the volume of the system is decreased? Options:
  A) H_2(g) + I_2(g) ≈ 2HI_(g)
  B) 2NO₂^(g) ≈ N₂O_4(g)O_4(g)N₂O_4(g)
  C) PCI_5(g) ≈ PCI_3(g) + CI_2(g)
  D) ZnO_(s) + CO_2(g) ≈ ZnCO_3(g)
  Show Answer
  The correct answer is D .
• Question 483: In the electrolytic extraction of cacium from calcium chloride, the cathode is Options:
  A) zinc
  B) graphite
  C) platinum
  D) iron
  Show Answer
  The correct answer is D .
• Question 484: 2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of? Options:
  A) constant composition
  B) conservation of mass
  C) reciprocal proportions
  D) multiple proportions
  Show Answer
  The correct answer is D .
• Question 485: Methylethanoate reacts with ammonia to yield? Options:
  A) mettylamine and ethanol
  B) ethylamine and methanol
  C) methanamide and ethanol
  D) ethanamide and methanol
  Show Answer
  The correct answer is D .
• Question 486: The effect of the presence of impurities such as carbon and sulphur on iron is that they Options:
  A) give it high tensile strenght
  B) make it malleable and ductile
  C) increase its melting point
  D) lower its melting point
  Show Answer
  The correct answer is D .
• Question 487:

  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) C${}_3$H${}_6$O${}_3$
  B) C${}_6$H${}_6$O${}_3$
  C) C${}_6$H${}_{12}$O${}_6$
  D) CH${}_2$O
  Show Answer
  The correct answer is C .
• Question 488:

  The following are isoelectronic ions except

  Options:
  A) Na${}^{+}$
  B) Mg${}^{2+}$
  C) Si${}^{2+}$
  D) O${}^{2+}$
  Show Answer
  The correct answer is C .
• Question 489: How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?(Ni = 58.7, 1F = 96 500 C mol^-) Options:
  A) 0.20
  B) 0.30
  C) 0.40
  D) 0.50
  Show Answer
  The correct answer is C .
• Question 490: Copper (II) tetraoxosulphate (IV) is widely used as a? Options:
  A) fertilizer
  B) fungicide
  C) disinfectant
  D) purifier
  Show Answer
  The correct answer is B .