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 1: If atom X with six electrons in its outermost shell combines with atom Y with one electron in its outermost shell to form an ionic compound, then? Options:
  A) six atoms of X will combine with one of Y
  B) two atoms of X will combine with six of Y
  C) one atom of X will combine with two of Y
  D) two atoms of X will combine with one of Y
  E) one atom of X will combine with six of Y
  Show Answer
  The correct answer is C .
• Question 2: A burning candle produces water and Options:
  A) Carbon (II) oxide
  B) Carbon (IV) oxide
  C) Oxygen
  D) Hydrogen
  Show Answer
  The correct answer is B .
• Question 3: Alloys are best prepared by? Options:
  A) high temperature weilding of the metals
  B) electrolysis using the major metallic component as cathode
  C) reducing a mixture of the oxies of the elements
  D) cooling a molten mixture of the necessary elements
  Show Answer
  The correct answer is D .
• Question 4: Which of the following solutions will conduct the least amount of electricity? Options:
  A) 2.00 M aqueous solution of NaOH
  B) 0.01 M aqueous solution of NaOH
  C) 0.01 M aqueous solution of hexanoic acid
  D) 0.01 M aqueous solution of sugar
  Show Answer
  The correct answer is D .
• Question 5:

  

  The arrangement above can be used for the collection of

  Options:
  A) sulphur (IV) oxide
  B) ammonia
  C) hydrogen chloride
  D) nitrogen
  Show Answer
  The correct answer is C .
• Question 6: Given the mean atomic mass of chlorine prepared in the laboratory to be 35.5 and assuming that chlorine contains two isotopes of mass number 35 nad 37, what is the percentage composition of the isotope of mass number 35? Options:
  A) 20
  B) 25
  C) 50
  D) 75
  E) 90
  Show Answer
  The correct answer is D .
• Question 7: An iron ore is known to contain 70.0% Fe₂O₃. The obtain from 80kg of the ore is?(Fe = 56, O = 16) Options:
  A) 35.0 kg
  B) 39.2 kg
  C) 70.0 kg
  D) 78.4 kg
  Show Answer
  The correct answer is B .
• Question 8: Water molecule can be ligands especially when they are bonded to Options:
  A) alkaline earth metals
  B) alkali metals
  C) transition metals
  D) group VII elements
  Show Answer
  The correct answer is C .
• Question 9: If the cost of electricity required to deposit 1 g of magnesium is ₦5.00, how much would it cost to deposit 10g of aluminium? Options:
  A) ₦10.00
  B) ₦27.00
  C) ₦44.44
  D) ₦66.67
  E) ₦33.33
  Show Answer
  The correct answer is D .
• Question 10: An anhydride is an oxide of non-mental? Options:
  A) which will not dissolve in water
  B) whose solution in water has a pH greater than 7
  C) whose solution in water has a pH less than 7
  D) whose solution in water has a pH of 7
  Show Answer
  The correct answer is C .