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: The droplets of water observed around a bottle of milk taken out of the refrigerator is due to the fact that the Options:
  A) water vapour in the air around the bottle gains some energy from the bottle
  B) temperature of the milk drops as it loses heat into the surroundings
  C) saturated vapour pressure of the milk is equal to the atmospheric pressure
  D) water vapour in the air around the bottle loses some of its energy to the bottle
  Show Answer
  The correct answer is D .
• Question 2: The minimum volume of oxygen required for the complete combustion of a mixture of 10cm ³ of CO and 15 cm ³ of H ² is Options:
  A) 25.0cm³
  B) 12.5 cm³
  C) 10.0 cm³
  D) 5.0cm³
  Show Answer
  The correct answer is C .
• Question 3: For iron to rust, there should be present? Options:
  A) oxygen
  B) moisture
  C) carbondioxide
  D) oxygen and moisture
  E) oxygen, moisture and carbondioxide
  Show Answer
  The correct answer is D .
• Question 4:

  Which of the following metals is commonly alloyed with copper to make brass?

  Options:
  A) Iron
  B) Nickel
  C) Aluminum
  D) Zinc
  Show Answer
  The correct answer is D .
• Question 5: If an equilibrium reaction has ∆H < O, the reaction will proceed favorably in the forward reaction at? Options:
  A) low temperatures
  B) high temperatures
  C) all temperatures
  D) all pressures
  Show Answer
  The correct answer is A .
• Question 6: When dilute hydrochloric acid is added to iron(ll)sulphide, the gas evolved will? Options:
  A) turn moist red litmus paper blue
  B) turn lime water milky
  C) blacken lead acurate paper
  D) rekindle a glowing splint
  E) burn a sqeakly pop
  Show Answer
  The correct answer is C .
• Question 7:

  Which quantum divides shells into orbitals?

  Options:
  A) Spin
  B) Principal
  C) Azimuthal
  D) Magnetic
  Show Answer
  The correct answer is C .
• Question 8: The solution with the lowest pH value is Options:
  A) 5 ml of (m/10) HCL
  B) 10 ml of (m/10) HCL
  C) 15 ml of (m/5) HCL
  D) 20 ml of (m/8) HCL
  Show Answer
  The correct answer is A .
• Question 9: The carbon atoms on ethane are? Options:
  A) sp² hybridized
  B) sp³ hybridized
  C) sp²d hybridized
  D) sp hybridized
  Show Answer
  The correct answer is B .
• Question 10:

  Cr₂O$\frac{2-}{7}$ (aq) + H₂O(1)⇌ 2CrO $\frac{2-}{4}$ (aq) + 2H ⁺ (aq)

  What happens to the reaction above when the hydrogen ion concentration is increased?

  Options:
  A) more of the products will be formed
  B) the reaction will not proceed
  C) the equilibrium position will shift to the right
  D) the equilibrium position will shift to the left.
  Show Answer
  The correct answer is D .