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 1241:

  56.00cm³ of a gas at S.T.P. weighed 0.11g. What is the vapour density of the gas?

  [Molar volume of a gas at S.T.P = 22.4dm³]

  Options:
  A) 11.00
  B) 22.00
  C) 33.00
  D) 44.00
  Show Answer
  The correct answer is B .
• Question 1242: A sample of temporary hard water can be prepared in the laboratory by? Options:
  A) disolving calcium chloride in distilled water
  B) saturating lime water with carbon (IV) oxide
  C) saturating distilled water with calcium hydroxide
  D) dissolving sodium hydrogen trioxocarbonate (IV) in some distilled water
  Show Answer
  The correct answer is B .
• Question 1243: Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys? Options:
  A) Tin
  B) Zinc
  C) Copper
  D) Lead
  E) Aluminium
  Show Answer
  The correct answer is C .
• Question 1244: Which of the following represents ethyl ethanonate? Options:
  A) CH₃CH₂CO₂CH₃
  B) (CH₃CO₂)₂O
  C) CH₃CH₂CO₂CH₂CH₃
  D) CH₃CO₂CH₂CH₃
  E) CH₃CH₂COCH₂CH₃
  Show Answer
  The correct answer is D .
• Question 1245: Two gas cylinders contain ethylene (ethene) and acetylene respectively. One test which can be used to distinguish between them is by Options:
  A) passing each gas through bromine water
  B) passing each gas through dilute potassium permanganate solution
  C) passing each gas through silver nitrate solution
  D) treating each gas catalytically with excess hydrogen gas
  Show Answer
  The correct answer is C .
• Question 1246:

  Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?

  Options:
  A) But-2-ene
  B) But-1-ene
  C) But-2-yne
  D) But-1-yne
  Show Answer
  The correct answer is D .
• Question 1247:

  The contact process is used for the industrial production of

  Options:
  A) sulfuric acid (H2SO4)
  B) Hydrochloric acid (HCl)
  C) Sodium hydroxide (NaOH)
  D) Calcium oxide (CaO)
  Show Answer
  The correct answer is A .
• Question 1248: In two separate experiments, 0.36g and 0.71g of chlorine combined with a metal X to give Y and Z respectively. An analysis showed that Y and Z contain 0.20g and 0.40g of X respectively. The data above represents the law of ? Options:
  A) multiple proportion
  B) conservation of mass
  C) constant composition
  D) reciprocal proportion
  Show Answer
  The correct answer is C .
• Question 1249: Chlorine gas turns a damp starch-iodide paper Options:
  A) pink
  B) colourless
  C) red
  D) dark blue
  Show Answer
  The correct answer is D .
• Question 1250: A mixture of common salt, ammonium chloride and barium sulphate can best be separated by Options:
  A) addition of water followed by filtration then sublimation
  B) addition of water followed by sublimation then filtration
  C) sublimation followed by addition of water then filtration
  D) fractional distillation
  E) fractional crystallization
  Show Answer
  The correct answer is C .