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 1601: An experiment produces a gaseous mixtures of carbon (IV) oxide and carbon (II) oxide. In order to obtain pure carbon (II) oxide, the gas mixture should be? Options:
  A) passed over heated copper (II) oxide
  B) bubbled through concentrated tetraoxosulphate (IV) acid
  C) bubbled through sodium hydroxide solution
  D) bubbled through water
  Show Answer
  The correct answer is C .
• Question 1602: On recrystallization, 20g of magnesium tetraoxosuphate (IV) forms 41 g of magnesium tetraoxosulphate (IV) crystals, MgSO₄. yH₂O. The value of y is?(Mg = 24, S = 32, O = 16, H = 1) Options:
  A) 1
  B) 3
  C) 5
  D) 7
  Show Answer
  The correct answer is D .
• Question 1603: How many hydrogen atoms does a single ring cycloalkane have less than the corresponding open-chain alkane? Options:
  A) Two
  B) Three
  C) Four
  D) One
  Show Answer
  The correct answer is A .
• Question 1604: Fluorine does not occur in the free state in nature because Options:
  A) it is a poisonous gas
  B) it belongs to the halogen family
  C) it is inert
  D) of its high reactivity
  Show Answer
  The correct answer is D .
• Question 1605:

  What is the maximum number of electrons that can occupy the second energy level (n=2)?

  Options:
  A) 2 electrons
  B) 18 electrons
  C) 8 electrons
  D) 32 electrons
  Show Answer
  The correct answer is C .
• Question 1606: The process of converting linear alkanes to branched chain and cyclic hydrocarbons by heating in the presence of a catalyst to improve the quality of petrol is referred to as Options:
  A) refining
  B) craching
  C) reforming
  D) blending
  Show Answer
  The correct answer is C .
• Question 1607:

  C₁₂H₂₂O_11(s) + H₂SO_4(aq) 12C_(s) + 11H₂O_(l) + H₂SO_4(aq)

  In the reaction above, tetraoxosulphate (VI) acid function as

  Options:
  A) A dehydrate agent
  B) An oxidizing agent
  C) A reducing agent
  D) A catalyst
  Show Answer
  The correct answer is A .
• Question 1608: Which of the following compounds is NOT the correct product formed when the parent metals is heated in air? Options:
  A) Calcium oxide (CaO)
  B) Sodium oxide (Na₂O)
  C) Copper (ll) oxide (CuO)
  D) Tri-iron tetroxide (Fe₃O₄)
  E) Aluminium oxide (Al₂O₃)
  Show Answer
  The correct answer is D .
• Question 1609: The fuming of kettles is caused by the presence in the water of Options:
  A) Calcium tetraoxosulphate (VI)
  B) Calcium hydrogentrioxocarbonate (IV)
  C) Calcium hydroxide
  D) Calcium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .
• Question 1610:

  A metal M displaces zinc from ZnCl, solution, solution

  This shows that

  Options:
  A) electrons flow from zinc to M
  B) M is more electropositive than zinc
  C) M is more electonegative than zinc
  D) zinc is more electropositive than M
  Show Answer
  The correct answer is B .