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 1621: 50 cm³ of gas was collected over water at 10^oC and 765 mm Hg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10 ^oC is 5mm Hg Options:
  A) 49.19 cm ³
  B) 48.87 cm ³
  C) 48.55 cm ³
  D) 48.23 cm ³
  Show Answer
  The correct answer is D .
• Question 1622: What mass of a divalent metal M (atomic mass = 40) would react with excess hydrogen gas measured at S.T.P? Options:
  A) 8.0 g
  B) 4.0 g
  C) 0.8 g
  D) 0.4 g
  Show Answer
  The correct answer is D .
• Question 1623: In which of the following is the oxidation state of oxygen different from its value in water? Options:
  A) OH^-
  B) H₃O⁺
  C) O^-
  D) H₂O₂
  E) SO₂
  Show Answer
  The correct answer is D .
• Question 1624: Local black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the? Options:
  A) acid
  B) ester of allanoic acid
  C) alkali
  D) alkanol
  Show Answer
  The correct answer is C .
• Question 1625: The uncovered raw food that is sold along major roads is likely to contain some amounts of Options:
  A) Pb
  B) Cu
  C) Ag
  D) Na
  Show Answer
  The correct answer is A .
• Question 1626:

  

  The oxidation of the compound above produces

  Options:
  A) 2-butanone
  B) 2-butanal
  C) 3-butanal
  D) 3-butanone
  Show Answer
  The correct answer is A .
• Question 1627: The component of an atom that contributes least to its mass is the Options:
  A) proton
  B) nucleus
  C) neutron
  D) electron
  Show Answer
  The correct answer is D .
• Question 1628: Vulcanization of rubber is a process by which Options:
  A) isoprene units are joined to produce rubber
  B) rubber latex is coagulated
  C) sulphur is chemically combined in the rubber
  D) water is removed from the rubber
  Show Answer
  The correct answer is C .
• Question 1629: The reaction of an alkene with hydrogen in the presence of catalyst is Options:
  A) a substitution reaction
  B) an oxidation reaction
  C) a nucleophilic reaction
  D) an addition reaction
  Show Answer
  The correct answer is D .
• Question 1630: What is the IUPAC nomenclature of the compound NaCIO? Options:
  A) sodium oxochlorate (I)
  B) sodium chloro (I) oxide
  C) sodium monooxochlorate (II)
  D) sodium chloro (I) monoxide
  Show Answer
  The correct answer is A .