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 881: Two metallic ions associated with hard water are Options:
  A) copper and zinc
  B) magnesium and silver
  C) calcium and magnesium
  D) potassium and tin
  E) sodium and lead
  Show Answer
  The correct answer is C .
• Question 882:

  Temp (°C)	25	35	45
  Time (seconds)	72	36	18

  The times taken for iodine to be liberated in the reaction between sodium thiosulphate and hydrochloric acid at various temperature are as follows. These results suggest that

  Options:
  A) for a 10^o rise in temperature, rate of reaction is double
  B) for a 10 ^o rise in temperature, rate of reaction is halved
  C) time taken for iodine to appear does not depend on temperature
  D) for a 10 ^o rise in temperature rate of reaction is tripled
  Show Answer
  The correct answer is A .
• Question 883: What amount of mercury would be liberated if the same quantity of electricity that liberates 0.65g of zinc is applied? Options:
  A) 2.01g
  B) 1.00g
  C) 4.02g
  D) 8.04g
  Show Answer
  The correct answer is C .
• Question 884: Hydrogen is used in oxy-hydrogen flames for melting metals because it Options:
  A) evolves a lot of heat when burnt
  B) combines explosively with oxygen
  C) is a very light gas
  D) is a rocket fuel
  Show Answer
  The correct answer is A .
• Question 885: The ores that can be concentrated by flotation are Options:
  A) nitride ores
  B) sulphide ores
  C) oxide ores
  D) non-metals
  Show Answer
  The correct answer is B .
• Question 886:

  

  The IUPAC nomenclature of the compound above is

  Options:
  A) 2-bromo-3-chlorobutanol
  B) 3-bromo-2-chlorobutanol
  C) 3-chloro-2-bromobutanol
  D) 2-chloro-3-bromobutanol
  Show Answer
  The correct answer is B .
• Question 887: In the extraction of iron, which of the following reactions does NOT take place in the blast furnace? Options:
  A) CO₂ + C → 2CO
  B) 2Fe₂O₃ + 3C → 4Fe + 3CO₂
  C) Fe₂O₃ + 3C → 2Fe + 3CO₂
  D) CaCO₃ → CaO + CO₂
  E) CaO + SiO₂ → CaSiO₃
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  The correct answer is B .
• Question 888: When ΔH is negative, a reaction is said to be Options:
  A) ionic
  B) reversible
  C) exothermic
  D) endothermic
  Show Answer
  The correct answer is C .
• Question 889: Arrange HCI, CH₃COOH, C₆H₅CH₃ in order of increasing conductivity. Options:
  A) HCI, CH₃COOH, C₆H₅CH₃
  B) C₆H₅CH₃, HCI, CH₃COOH
  C) C₆H₅CH₃, CH₃COOH, HCI
  D) CH₃COOH, C₆H₅CH₃, HCI
  Show Answer
  The correct answer is C .
• Question 890: Kerosine is commonly used to remove the red colour stain of palm oil from cloths because it Options:
  A) helps to spread the oil over a larger surface area
  B) react with the oil to form an odourless compound
  C) makes the oil evaporate easily by dissolving it
  D) helps to dilute the oil and reduce its colour
  Show Answer
  The correct answer is C .