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:

  

  In the diagram above, the gas produced is

  Options:
  A) NO
  B) NO₂
  C) N₂O
  D) N₂O₄
  Show Answer
  The correct answer is A .
• Question 2: 2SO_2(g) + O_2(g) ↔ 2SO_3(g). In the chemical reaction above, the substance that will increase the rate of production of sulphur (VI) oxide is Options:
  A) manganese (IV) oxide
  B) finely divided iron
  C) vanadium (V) oxide
  D) nickel
  Show Answer
  The correct answer is C .
• Question 3:

  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 4: The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ? Options:
  A) 45
  B) 55
  C) 80
  D) 100
  Show Answer
  The correct answer is B .
• Question 5: How many protons, neutrons and electrons respectively are present in the element 60/27 Co? Options:
  A) 27, 33 and 33
  B) 33, 27 and 27
  C) 27, 33, and 27
  D) 60, 33 and 60
  Show Answer
  The correct answer is C .
• Question 6:

  

  The compound above exhibits

  Options:
  A) geometric isomerism
  B) optical isomerism
  C) structural isomerism
  D) positional isomerism
  Show Answer
  The correct answer is B .
• Question 7: Three solutions contain carbonate, sulphate and sulphide ions respectively. One test that will identify just ONE of them completely is by addition to each of them of Options:
  A) barium chloride solution
  B) dilute hydrochloric acide
  C) lead nitrate solution
  D) calcium chloride solution
  E) sodium hydroxide solution
  Show Answer
  The correct answer is C .
• Question 8: The most abundant element on the earth's crust is Options:
  A) nitrogen
  B) hydrogen
  C) oxygen
  D) flourine
  Show Answer
  The correct answer is C .
• Question 9:

  Calculate the volume in cm³ of oxygen evolved at s.t.p when a current of 5A is passed through acidified water for 193s?

  [F = 96500 C mol¹. Molar volume of a gas at s.t.p = 22.4dm³]

  Options:
  A) 0.056dm³
  B) 0.224dm³
  C) 224.000dm³
  D) 56.000dm³
  Show Answer
  The correct answer is A .
• Question 10:

  In the upper atmosphere, the ultra-violet light breaks off a free chlorine atom from chlorofluorocarbon molecule. The effect of this is that the free chlorine atom will

  Options:
  A) be very reactive and will attack ozone
  B) be non-reactive and will not attack ozone
  C) not change the level of ozone in the atmosphere
  D) increase the level of ozone in the atmosphere
  Show Answer
  The correct answer is A .