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 531: Sugar is separated from its impurities by Options:
  A) precipitation
  B) crystallization
  C) distillation
  D) evaporation
  Show Answer
  The correct answer is B .
• Question 532: Powdered marble reacts faster with hydrochloric acid solution than the granular form because the powdered form has Options:
  A) more molecules
  B) more atoms
  C) larger surface area
  D) relatively large mass
  Show Answer
  The correct answer is C .
• Question 533: If the rate law obtained for a given reaction is rate = k(X)ⁿ (Y)^m, what is the overall order of the reaction? Options:
  A) nm
  B) n/m
  C) n + m
  D) n - m
  Show Answer
  The correct answer is C .
• Question 534:

  

  It can be deduced from the vapour pressure curves above that

  Options:
  A) liqiud 1 has the highest boiling point
  B) liquid ll has the highest boiling point
  C) liquid lll has the highest boiling point
  D) liquid lll has the lowest boiling point
  Show Answer
  The correct answer is C .
• Question 535:

  

  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 536: When ethanol is heated with excess concentrated sulphuric acid, the ethanol is? Options:
  A) oxidized to ethene
  B) polymerized to polyethene
  C) dehydrated to ethene
  D) dehydrated to ethyne
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  The correct answer is C .
• Question 537: The shape of the hydrocarbon compound CH₄ is Options:
  A) square planar
  B) planar
  C) linear
  D) tetrahedral
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  The correct answer is D .
• Question 538: The type of iron that is best suited for welding, making nails, chains and iron rods is Options:
  A) pig iron
  B) wrought iron
  C) cast iron
  D) iron pyrites
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  The correct answer is B .
• Question 539: Lime - water, which is used in the laboratory for the detection of carbon(iv)oxide is an aqueous solution of Options:
  A) Ca(OH)₂
  B) CaCO₃
  C) CaHCO₃
  D) CaSO₄
  E) N₂CO₃
  Show Answer
  The correct answer is A .
• Question 540:

  If the molecular mass of tetraoxosulphate (VI) acid is 98, calculate its vapour density.

  Options:
  A) 196
  B) 49
  C) 106
  D) 82
  Show Answer
  The correct answer is B .