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 811: The energy value of petrol can be determined by a Options:
  A) bomb calorimeter
  B) catalytic cracker
  C) fractionating column
  D) thermometer
  Show Answer
  The correct answer is C .
• Question 812: The products of the reaction between dilute sulphuric acid and sodium thiosulphate crystals are? Options:
  A) Na₂SO₄ + SO₂ + O₂ + H₂O
  B) Na₂SO₃ + SO₃ + O₂ + H₂O
  C) Na₂SO₄ + SO₂ + S + H₂O
  D) Na₂SO₄ + SO₃ + S + H₂O
  E) Na₂SO₄ + SO₂ + H₂O only
  Show Answer
  The correct answer is C .
• Question 813:

  What is the concentration of a solution containing 2g of NaOH in 100cm³ of solution?

  [Na=23, O=16, H=1]

  Options:
  A) 0.05 moldm^-3
  B) 0.30 moldm^-3
  C) 0.50 moldm^-3
  D) 0.40 moldm^-3
  Show Answer
  The correct answer is C .
• Question 814: When steam is passed through red hot carbon, which of the following are produced? Options:
  A) Hydrogen oxygen and carbon (IV) oxide
  B) Hydrogen and carbon (IV) oxide
  C) Hydrogen and carbon (II) oxide
  D) Hydrogen and trioxocarbonate (IV) acid
  Show Answer
  The correct answer is C .
• Question 815: When a solution of silver (l) nitrate is saturated with hydrogen sulphide, a black precipitate forms which is? Options:
  A) H₂S
  B) Ag₂S
  C) PbS
  D) HNO₃
  E) S
  Show Answer
  The correct answer is B .
• Question 816: Which of the following equations show that a reaction is in equilibrium?
  Options:
  A) ΔG < O
  B) ΔG = ΔH – TΔS
  C) ΔG > O
  D) ΔG = O
  Show Answer
  The correct answer is D .
• Question 817:

  Which of the following is used to power steam engines?

  Options:
  A) lubricating oil
  B) coal
  C) bitumen
  D) diesel oil
  Show Answer
  The correct answer is B .
• Question 818: Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs) Options:
  A) 0.457g
  B) 0.500g
  C) 0.882g
  D) 0.914g
  E) 1.00g
  Show Answer
  The correct answer is A .
• Question 819:

  The combustion of carbon(ii)oxide in oxygen can be represented by equation.

  2CO + O${}_2$ → 2CO${}_2$

  Calculate the volume of the resulting mixture at the end of the reaction if 50cm${}_3$ of carbon(ii)oxide was exploded in 100cm${}_3$ of oxygen

  Options:
  A) 75cm${}^3$
  B) 125cm${}^3$
  C) 100cm${}^3$
  D) 50cm${}^3$
  Show Answer
  The correct answer is B .
• Question 820:

  The reactions involving simultaneous oxidation and reduction?

  Options:
  A) Automatic reactions
  B) Alternate reactions
  C) Reduction agency
  D) Redox reactions
  Show Answer
  The correct answer is D .