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 1121: There is a large temperature interval between the melting point and the boiling point of a metal because? Options:
  A) metals have very high melting points
  B) metals conduct heat very rapidly
  C) melting does not break the metallic bond but boiling does
  D) the crystal lattice of metals is easily broken
  Show Answer
  The correct answer is C .
• Question 1122: An elements used in production of matches is Options:
  A) nitrogen
  B) aluminum
  C) copper
  D) sulphur
  Show Answer
  The correct answer is D .
• Question 1123: The reddish-brown rust on iron roofing sheets consists of Options:
  A) Fe³⁺(H₂O)₆
  B) FeO.H₂O
  C) Fe₂O₃.3H₂O
  D) Fe₃O₄.2H₂O
  Show Answer
  The correct answer is C .
• Question 1124:

  Potassium trioxochlorate (V)has a solubility of 1.5 mol dm ^-3 at 45 ^oC.On cooling this solution to a temperature of 20 ^oC, the solubility was found to be 0.5 mol dm ^-3. What mass of KCIO ₃ was crystalized out?

  [K = 39, Cl = 35.5 O =16].

  Options:
  A) 1.00g
  B) 10.00g
  C) 12.25g
  D) 122.50g
  Show Answer
  The correct answer is D .
• Question 1125:

  Which of the following represents the kind of bonding present in ammonium chloride?

  Options:
  A) ionic only
  B) covalent only
  C) ionic and dative covalent
  D) dative covalent
  Show Answer
  The correct answer is C .
• Question 1126: The reaction between ammonia and ethyl ethanoate produces Options:
  A) propanol and ethanamide
  B) propanol and propanamide
  C) ethanol and propanamide
  D) ethanol and ethanamide
  Show Answer
  The correct answer is D .
• Question 1127:

  A solution contains 20g of solute in 180g of solvent. If the solvent is water, what is the concentration of the solution in terms of mass by mass percentage

  Options:
  A) 11.%
  B) 22.2%
  C) 10%
  D) 20%
  Show Answer
  The correct answer is C .
• Question 1128:

  Which of the following gases will rekindle a brightly splint?

  Options:
  A) NO${}_2$
  B) NO
  C) N${}_2$O
  D) CL${}_2$
  Show Answer
  The correct answer is C .
• Question 1129: A primary amide is generally represented by the formula Options:
  A) RCOOR
  B) RCONH ₂
  C) RCONHR
  D) RCONR ₂
  Show Answer
  The correct answer is B .
• Question 1130: What is the oxidation number of Z in K₃ZCl₆? Options:
  A) -3
  B) +3
  C) -6
  D) +6
  Show Answer
  The correct answer is B .