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 1311: When temporary hard water is boiled for sometime in a kettle, the inner surface of the kettle becomes coated with a deposit of Options:
  A) calcium tetraoxosulphate(VI)
  B) calcium trioxocarbonate (IV)
  C) calcium hydrogentrioxocarbonate (IV)
  D) aluminium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .
• Question 1312:

  A gaseous metallic chloride MCl_x consists of 20.22% of M by mass. The formula of the chloride is

  [M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl₂
  C) MCl₃
  D) M₂Cl₆
  Show Answer
  The correct answer is C .
• Question 1313:

  The two ions responsible for hardness in water are

  Options:
  A) Ca${}^{2+}$ and / or Mg${}^{2+}$
  B) K${}^{+}$ and / or Mg${}^{2+}$
  C) Ca${}^{2+}$ and / or Li${}^{+}$
  D) Ca${}^{2+}$ and / or Na${}^{+}$
  Show Answer
  The correct answer is A .
• Question 1314: Which of the following is a measure of the average kinetic energy of the molecules of a substance? Options:
  A) Volume
  B) Mass
  C) Pressure
  D) Temperature
  Show Answer
  The correct answer is D .
• Question 1315: Which of the following metals is passive to concentrated trioxonitrate (V) acid? Options:
  A) Iron
  B) Tin
  C) Copper
  D) Zinc
  Show Answer
  The correct answer is A .
• Question 1316:

  

  The diagram above best illustrates the effect of decrease in

  Options:
  A) concentration
  B) temperature
  C) surface area
  D) pressure
  Show Answer
  The correct answer is A .
• Question 1317: Benzene reacts with hydrogen in the presence of nickel catalyst at 180^oC to give Options:
  A) xylene
  B) toluene
  C) cyclopentane
  D) cyclohexane
  Show Answer
  The correct answer is D .
• Question 1318: Cu₂S_(s) + O2(g) = 2CU_(s) + SO2_2(g) Options:
  A) +1 to 0
  B) 0 to +2
  C) +2 to +1
  D) 0 to +1
  Show Answer
  The correct answer is A .
• Question 1319: In which of the following reactions is sulphur dioxide acting as an oxidizing agent? Options:
  A) SO ₂ + 2HNO₃ →H₂SO₄ + NO₂ + Heat
  B) 2SO₂ + 2H₂O + O₂→ 2H₂SO₄
  C) SO₂ + 2H₂O + CI₂→ H₂SO₄ + 2HCI
  D) SO₂ + 2H₂S → 3S + 2H₂O
  E) SO₂ + H₂O → H₂SO₃
  Show Answer
  The correct answer is D .
• Question 1320: Which of the following decreases when a given mass of gas is compressed to half its initial volume? Options:
  A) Average intermolecular distance
  B) Frequency of collisions
  C) Number of molecules present
  D) Atomic radius of each particle
  Show Answer
  The correct answer is A .