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 31: 30cm³ of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C? Options:
  A) 40.0 cm³
  B) 35.7 cm³
  C) 28.4 cm³
  D) 25.2 cm³
  Show Answer
  The correct answer is C .
• Question 32: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 33:

  Stainless steel is an alloy made up of

  Options:
  A) Iron and zinc
  B) Copper and tin
  C) Iron and chromium
  D) Iron and carbon
  Show Answer
  The correct answer is C .
• Question 34: When air is passed through alkaline pyrogallol and then over quicklime, the only gases left are? Options:
  A) nitrogen and carbondoxide
  B) the rare gases
  C) nitrogen and oxygen
  D) nitrogen and the rare gases
  E) nitrogen, carbonioxide and the rare gases
  Show Answer
  The correct answer is D .
• Question 35:

  Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

  Options:
  A) P will form an electrovalent bond with R
  B) Q will form a covalent bond with S
  C) R will form an electrovalent bond with S
  D) Q will form an electrovalent bond with S
  Show Answer
  The correct answer is D .
• Question 36: The substance least considered as a source of environmental pollution is Options:
  A) Lead compounds
  B) Organophosphorous compounds
  C) Silicate minerals
  D) Uranium
  Show Answer
  The correct answer is C .
• Question 37: The nitrogen gas obtained by burning an excess of phosphorus in air has a density higher than the nitrogen from nitrogen compounds because the nitrogen from air is contaminated with? Options:
  A) some unburnt phosporus
  B) P₂O₅ vapour
  C) some oxygen
  D) rare gases
  E) carbondioxide
  Show Answer
  The correct answer is D .
• Question 38: The energy value of petrol can be determined by Options:
  A) Bomb calorimeter
  B) Catalytic cracker
  C) Fractionating column
  D) Thermometer
  Show Answer
  The correct answer is C .
• Question 39:

  At room temperature and standard pressure, chlorine gas is in which state of matter?

  Options:
  A) Plasma
  B) Solid
  C) Liquid
  D) Gas
  Show Answer
  The correct answer is D .
• Question 40: Catalytic hydrogenation of benzene produces? Options:
  A) an aromatic hydrocarbon
  B) margarine
  C) cyclohexane
  D) D.D.T
  Show Answer
  The correct answer is C .