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 1471: The periodic classification of elements is an arrangement of the elements in order of their Options:
  A) Atomic Weights
  B) Isotopic Weights
  C) Molecular Weights
  D) Atomic Numbers
  E) Atomic Masses
  Show Answer
  The correct answer is D .
• Question 1472:

  An organic compound with a vapour density 56.5 has the following percentage composition:C =53.1% N = 12.4%, O = 28.3%, H = 6.2%. The molecular formula of the compound is

  Relative atomic masses: N = 14, O = 16, C = 12, H = 1 )

  Options:
  A) C₃H₆O₂N
  B) C₅H₆O₂N
  C) (C₅H₇O₂N)_1/2
  D) C₅H₇O₂N
  E) (C₅H₇O₂N)₂
  Show Answer
  The correct answer is D .
• Question 1473:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 1474: Calculate the volume of 0.5 mol dm^-3 H₂So₄ that is neutralized by 25 cm³ of 0.1 mol dm^-3 NaOH Options:
  A) 5.0 cm³
  B) 2.5 cm³
  C) 0.4 cm³
  D) 0.1 cm³
  Show Answer
  The correct answer is B .
• Question 1475: The formula CH₂ for ethanoic acid is regarded as its Options:
  A) Molecular formula
  B) General formula
  C) Empirical formula
  D) Structural formula
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  The correct answer is C .
• Question 1476: Chlorine, bromine and iodine resemble one another in that they Options:
  A) dissolve in alkalis
  B) react violently with hydorgen without heating
  C) are liquids
  D) displace one another from solutiions of their salts
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  The correct answer is D .
• Question 1477: A liquid that will dissolve fat is Options:
  A) hydrochloric acid
  B) calcium hydrochloride
  C) kerosene
  D) water
  Show Answer
  The correct answer is C .
• Question 1478: A noble gas with a high power of fog penetration used in aerodrome beacons is Options:
  A) krpton
  B) argon
  C) helium
  D) neon
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  The correct answer is D .
• Question 1479:

  The ratio of the initial to the final pressure of a given mass of gas is 1:1.5. Calculate the final volume of the gas if the initial volume was 300cm${}^3$ at the same temperature.

  Options:
  A) 120cm${}^3$
  B) 200cm${}^3$
  C) 450cm${}^3$
  D) 750cm${}^3$
  Show Answer
  The correct answer is B .
• Question 1480: The solution of a sample in a tube will be identified as a chloride if it gives Options:
  A) a white precipitate on addition of AgNO₃ and barium chloride solutions
  B) a white precipiate when acidified with HCI, and then AgNO₃ solution added
  C) a white precipitate when acidified with dilute HNO₃ and then AgNO₃ solution added
  D) a white precipitate when acidified with dilute H₂SO₄ and then barium nitrate solution added
  E) a pungent smell of chlorine gas when dilute HCI and MnO₂ are added
  Show Answer
  The correct answer is C .