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 551: An organic compound decolourized acidified KMnO₄ solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be? Options:
  A) a carbonxylic acid
  B) an alkane
  C) an alkene
  D) an alkyne
  E) an akanone
  Show Answer
  The correct answer is C .
• Question 552:

  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 553: Polyvinyl chloride is used in the production of Options:
  A) glass
  B) alloy
  C) pipes
  D) ceramics
  Show Answer
  The correct answer is C .
• Question 554: When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes? Options:
  A) X/4 g
  B) X/2 g
  C) 2X g
  D) 4X g
  Show Answer
  The correct answer is B .
• Question 555:

  What weight of NaCl is needed to make 2.0 dm³ of a 1.5M solution?

  [Na = 23, Cl = 35.5]

  Options:
  A) 116 g
  B) 175 g
  C) 87 g
  D) 58 g
  Show Answer
  The correct answer is B .
• Question 556:

  A given amount of gas occupies 10.0 dm³ at atm, and 273°C. The number of moles of the gas present is?

  (Molar volume of a gas at s.t.p. = 22.4 dm³)

  Options:
  A) 0.89 mol
  B) 1.90 mol
  C) 3.80 mol
  D) 5.70 mol
  Show Answer
  The correct answer is B .
• Question 557:

  The products of the thermal decomposition of ammonium trioxonitrate(v) are?

  Options:
  A) Nitrogen (I) Oxide and Water
  B) Ammonia and Oxide
  C) Nitrogen and Water
  D) Nitrogen (IV) Oxide and Water
  Show Answer
  The correct answer is A .
• Question 558: The simplest branched-chain hydrocarbon is Options:
  A) ethane
  B) ethene
  C) propane
  D) butane
  Show Answer
  The correct answer is D .
• Question 559:

  

  The function of the copper (ll)tetraoxosulphate (IV) in dilute H₂SO₄ in the figure above is to

  Options:
  A) dry the gas
  B) absorb phosphine impurity
  C) absorb ethene impurity
  D) from an acetylide with ethyne
  Show Answer
  The correct answer is B .
• Question 560: One mole of hydrocarbon contains 6g of hydrogen. If the molecular weight is 54, the hydrocarbon is an? Options:
  A) alkanone
  B) alkane
  C) alkene
  D) alkyne
  Show Answer
  The correct answer is D .