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 81: In the laboratory preparation of ammonia, the flask is placed in a slanting position so as to Options:
  A) prevent condensed water from breaking the reaction flask
  B) enable the proper mixing of the reactions in the flask
  C) enhance the speed of the reaction
  D) prevent formation of precipitate
  Show Answer
  The correct answer is A .
• Question 82:

  

  Use the diagram to answer this question.

  The colour of the fountain water is

  Options:
  A) blue
  B) orange
  C) red
  D) yellow
  Show Answer
  The correct answer is C .
• Question 83: Which of the following statements is correct during the electrolysis of a caustic soda solution using platinum electrodes? Options:
  A) Oxygen gas is given off at the cathode
  B) Hydrogen gas is given of at the anode
  C) Sodium metals is deposited at the anode
  D) Sodium metal is deposited at the cathode
  E) AAlkalinity at the cathode increases
  Show Answer
  The correct answer is E .
• Question 84:

  

  In the experiment above, X is a mixture of nitrogen, carbon (IV) oxide and

  Options:
  A) water
  B) impurities
  C) inert gas
  D) oxygen
  Show Answer
  The correct answer is C .
• Question 85:

  How many grams of H₂SO₄ are necessary for the preparation of 0.175 dm³ of M 6.00 M H₂SO₄?

  (S = 32.06, O = 16.00 H = 1.00)

  Options:
  A) 206.0 g
  B) 103.0 g
  C) 98.1 g
  D) 51.5 g
  Show Answer
  The correct answer is B .
• Question 86:

  At 2.0 atm pressure, the volume of a gas is 4.0 L. If the pressure is reduced to 1.0 atm while keeping the temperature constant, what will be the new volume of the gas?

  Options:
  A) 2.0 L
  B) 6.0 L
  C) 8.0 L
  D) 4.0 L
  Show Answer
  The correct answer is C .
• Question 87: Ca(OH)_2(s) + 2NH₄Cl_(g) → CaCl_2(s) + 2H₂O_2(l) + X. In the reaction above X is Options:
  A) NO₂
  B) NH₃
  C) N₂O
  D) NO₂
  Show Answer
  The correct answer is B .
• Question 88:

  What is the chemical name for the compound CuCO${}_3$?

  Options:
  A) Copper (iii) carbonate
  B) Copper (ii) carbonate
  C) Copper (i) carbonate
  D) Copper
  Show Answer
  The correct answer is B .
• Question 89:

  Which organic compound is responsible for the characteristic aroma of fruits?

  Options:
  A) Alkane
  B) Alkyne
  C) Ester
  D) Amine
  Show Answer
  The correct answer is C .
• Question 90:

  H₃PO_4(aq) + H₂O_(l) ↔ H₂PO₄^-_(aq) + H₃O⁺_(aq)

  ΔH = -13kJ at 298K

  In the reaction above, an increase in temperature would

  Options:
  A) slow downthe reverse reaction
  B) have no effect on the reaction
  C) favour the reverse reaction
  D) favour the forward reaction
  Show Answer
  The correct answer is C .