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 1221: Which of the following ions require the largest quantity of electricity for discharge at an electrode? Options:
  A) 4.0 moles of Cl^-
  B) 3.0 moles of Na⁺
  C) 2.5 moles of Cu²⁺
  D) 2.0 moles of Al³⁺
  Show Answer
  The correct answer is C .
• Question 1222: A mixture of 0.20 mole of Ar, 0.20 mole of N₂ and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is? Options:
  A) 0.90 atm
  B) 0.80 atm
  C) 0.70 atm
  D) 0.60 atm
  Show Answer
  The correct answer is A .
• Question 1223:

  In electrovalency, the oxidation number of the participating metal is always

  Options:
  A) decreasing
  B) increasing
  C) constant
  D) neutral
  Show Answer
  The correct answer is C .
• Question 1224: If 0.75 mole of cyclopropane and 0.66 mole of oxygen are mixed in vessel with a total pressure of 0.7 atmosphere, what is the partial pressure of oxygen in the mixture Options:
  A) 0.44 atmosphere
  B) 0.22 atmosphere
  C) 0.55 atmosphere
  D) 0.33 atmosphere
  Show Answer
  The correct answer is D .
• Question 1225: When a bottle of Coca-Cola is opened, bubbles of evolve. The gas is? Options:
  A) hydrogen
  B) carbon monoxide
  C) carbon dioxide
  D) sulphur oxide
  E) chlorine
  Show Answer
  The correct answer is C .
• Question 1226: Hardening of an oil may be achieved by? Options:
  A) boiling the oil with water
  B) boiling the oil with a catalyst
  C) treating the oil with sodium hydroxide
  D) treating the oil with hydrogen and catalyst
  E) distilling oil under reduced pressure
  Show Answer
  The correct answer is D .
• Question 1227: The approximate volume of air containing 10cm³ of oxygen is? Options:
  A) 20 cm³
  B) 25 cm³
  C) 50 cm³
  D) 100 cm³
  Show Answer
  The correct answer is C .
• Question 1228: What is the partial pressure of hydrogen gas collected over water at standard atmospheric pressure and 25^oC if the saturation vapour pressure of water at saturation vapour pressure of water is 23 mm Hg at that temperature? Options:
  A) 737 mm Hg
  B) 763 mm Hg
  C) 777 mm Hg
  D) 783 mm Hg
  Show Answer
  The correct answer is A .
• Question 1229: Which of the following statements is NOT correct? Options:
  A) The average kinetic energy of a gas is directly proportional to its temperature
  B) At constant tempearture, the volume of a gas increases as the pressure increases
  C) The pressure of a gas is inversely proportional to its volume
  D) The temperature of a gas is directly proportional to its volume
  E) The collisions of molecules with each other are inelastic
  Show Answer
  The correct answer is B .
• Question 1230:

  When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is

  Options:
  A) propylmethanoate
  B) ethylpropanoate
  C) methyl ethanoate
  D) methyl propanoate
  Show Answer
  The correct answer is B .