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 61:

  Which of the following pairs cannot be represented with a chemical formula?

  Options:
  A) air and bronze
  B) bronze and sodium chloride
  C) copper and sodium chloride
  D) caustic soda and washing soda
  Show Answer
  The correct answer is A .
• Question 62:

  

  It can be deduced from the vapour pressure curves above that

  Options:
  A) liqiud 1 has the highest boiling point
  B) liquid ll has the highest boiling point
  C) liquid lll has the highest boiling point
  D) liquid lll has the lowest boiling point
  Show Answer
  The correct answer is C .
• Question 63:

  Temp (°C)	25	35	45
  Time (seconds)	72	36	18

  The times taken for iodine to be liberated in the reaction between sodium thiosulphate and hydrochloric acid at various temperature are as follows. These results suggest that

  Options:
  A) for a 10^o rise in temperature, rate of reaction is double
  B) for a 10 ^o rise in temperature, rate of reaction is halved
  C) time taken for iodine to appear does not depend on temperature
  D) for a 10 ^o rise in temperature rate of reaction is tripled
  Show Answer
  The correct answer is A .
• Question 64: wH₂SO₄ + xAI(OH)₃ → yH₂O + = zAI₂(SO₄)₃. The respective values of w.x.y and z in the equation above are? Options:
  A) 2,2,5 and 1
  B) 3,2,5 and 2
  C) 3,2,6 and 1
  D) 2,2,6 and 2
  Show Answer
  The correct answer is C .
• Question 65: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 66: How many faraday of electricity is required to produce 0.25 mole of copper? Options:
  A) 1.00F
  B) 0.01F
  C) 0.05F
  D) 0.50F
  Show Answer
  The correct answer is D .
• Question 67: The polymer used in making car rear lights is Options:
  A) perspex
  B) bakeelite
  C) polystyrene
  D) polyacrylonitrile
  Show Answer
  The correct answer is A .
• Question 68: In the preparation of carbon monoxide by heating ethanedioic acid with concentrated sulphuric acid, the concentrated sulphuric acid act as? Options:
  A) an oxidizing agent
  B) a reducing agent
  C) a dehydrating agent
  D) a reaction medium
  E) a catalyst
  Show Answer
  The correct answer is C .
• Question 69:

  In the reaction H_2(g)O $\to$ H_2(g) + 1/2O_2(g)

  ΔH = -2436000 KJ, which of the following has no effect on the equilibrium position?

  Options:
  A) Adding argon to the system
  B) Lowering the temperature
  C) Adding hydrogen to the system
  D) Decreasing the pressure
  E) Increasing the temperature
  Show Answer
  The correct answer is A .
• Question 70: Which of the following derivatives of nitrogen affords an aqueous solution having a pH of less that 7? Options:
  A) N₂O
  B) NO
  C) NO₂
  D) NaNO₃
  E) NH₃
  Show Answer
  The correct answer is C .