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 1301: The entropy and enthalpy of a system are a measure of Options:
  A) degree of disorderlinesss and heat content respectively
  B) heat content and degree of disorderliness respectively
  C) heat content of a system only
  D) degree of disorderliness only
  Show Answer
  The correct answer is A .
• Question 1302: Crude copper could be purified by the electrolysis of concentrated copper (II) chloride if the crude copper is? Options:
  A) made both the anode and the cathode
  B) made the cathode
  C) made the anode
  D) dissolved in the solution
  Show Answer
  The correct answer is C .
• Question 1303:

  The part of the total energy of a system that accounts for the useful work done in a system is known as

  Options:
  A) Enthalpy change
  B) None of the above
  C) Gibb's free energy
  D) Entropy
  Show Answer
  The correct answer is C .
• Question 1304: One mole of a hydrocarbon contains 48 g of carbon. If it vapour density is 28, the hydrocarbon is? Options:
  A) an alkane
  B) an alkene
  C) an alkyne
  D) aromatic (C = 12, H = 1)
  Show Answer
  The correct answer is B .
• Question 1305: Oxygen gas can be prepared by heating? Options:
  A) ammonium trioxonitrate (V)
  B) ammonium trioxonitrate (III)
  C) ppotassium trioxonitrate (V)
  D) mamgamese (IV) oxide
  Show Answer
  The correct answer is C .
• Question 1306: Synthesis gas is a mixture of Options:
  A) CH₄ and H₂O
  B) CH₄ and H₂
  C) CO₂ and H₂
  D) CO and H₂
  Show Answer
  The correct answer is D .
• Question 1307: Chlorine gas is prepared in the laboratory by Options:
  A) adding concentrated hydrochloric acid to solid manganese (IV) oxide
  B) aciding concentrated tetraoxosulphate (VI) acid to solid sodium chloride
  C) dropping concentrated hydrochloric acid onto potassium tetraoxomanganate (VI) crystals
  D) aciding concentrated tetraoxosulphate (VI) acid to hydrochloric acid
  Show Answer
  The correct answer is A .
• Question 1308:

  An element Z contains 80% of ${}_8^{16}$Z and 20% of ${}_8^{18}$Z. Its relative atomic mass is

  Options:
  A) 16.2
  B) 17.6
  C) 16.0
  D) 16.4
  Show Answer
  The correct answer is D .
• Question 1309:

  Which of the following gases can best be used for demonstrating the fountain experiment?

  (iv) Hydrogen chloride.

  Options:
  A) ii and iii
  B) i and iii
  C) ii and iv
  D) ii only
  E) Nitrogen (ii) Ammonia (iii) Nitrogen (I) oxide
  Show Answer
  The correct answer is C .
• Question 1310: Aromatic and aliphatic hydrocarbons can be distinguished from each other by the? Options:
  A) action of bromine
  B) use of polymerization reaction
  C) action of heat
  D) use of oxidation reaction
  Show Answer
  The correct answer is C .