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 541:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 542: Calculate the mass of copper deposited when a current of 0.5 ampere was passed through a solution of copper(II) chloride for 45 minutes in an electrolytic cell. [Cu = 64, F = 96500Cmol^-1] Options:
  A) 0.300g
  B) 0.250g
  C) 0.2242g
  D) 0.448g
  Show Answer
  The correct answer is D .
• Question 543:

  The heat of reaction can be determined experimentally using a device called a

  Options:
  A) Calorimeter
  B) Barometer
  C) Spectrometer
  D) Thermometer
  Show Answer
  The correct answer is A .
• Question 544: Aluminium containers are frequently used to transport trioxonitrate (V) acid because aluminium Options:
  A) has a silvery-white appearance
  B) has a low density
  C) does not react with the acid
  D) does not corrode
  Show Answer
  The correct answer is C .
• Question 545: Commercial bleaching can be carried out using Options:
  A) sulphur (IV) oxide and ammonia
  B) hydrogen sulphide and chlorine
  C) chlorine and sulphur (IV) oxide
  D) ammonia and chlorine
  Show Answer
  The correct answer is C .
• Question 546:

  Calculate the pH of 0.05 moldm${}^{-3}$ H${}_2$SO${}_4$

  Options:
  A) 1.30
  B) 1.12
  C) 1.00
  D) 0.30
  Show Answer
  The correct answer is A .
• Question 547:

  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 548: Natural water collected from rivers and ponds contain oxygen, carbon (IV) oxide and Options:
  A) nitrogen
  B) hydrogen
  C) chlorine
  D) sulphur
  E) oxide
  Show Answer
  The correct answer is A .
• Question 549:

  The mass number of a nucleus is?

  Options:
  A) Always less than its atomic number
  B) The sum of the number of protons and neutrons present in the nucleus
  C) Always more than the atomic weight
  D) A fraction
  Show Answer
  The correct answer is B .
• Question 550: Which of the following ions require the largest quantity of electricity for discharge at an electrode? Options:
  A) 2.0 mole of Q ³⁺
  B) 2.5 mole of R²⁺
  C) 4.0 mole of Y^-
  D) 3.0 mole of T^-
  Show Answer
  The correct answer is A .