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 351:

  PCl_5(g) ↔ PCl_3(g) + Cl_2(g)

  In the reaction above, a decrease in pressure will

  Options:
  A) Decelerate the reaction
  B) Increase the yield of PCl₃
  C) Increase the yield of PCl₅
  D) Accelerate the reaction
  Show Answer
  The correct answer is B .
• Question 352: A saturated solution of AgCl was found to have a concentration of 1.30 x 10^-5 mol dm^-3. The solubility product of AgCl therefore is? Options:
  A) 1.30 x 10^-5 mol₂ dm^-6
  B) 1.30 x 10^-7 mol₂ dm^-6
  C) 1.69 x 10^-10 mol₂ dm^-6
  D) 2.60 x 10^-12 mol₂ dm^-6
  Show Answer
  The correct answer is C .
• Question 353: A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is Options:
  A) 1,800 kg
  B) 900 kg
  C) 600 kg
  D) 2, 400 kg
  E) 1, 200 kg
  Show Answer
  The correct answer is D .
• Question 354: The carbon atoms on ethane are Options:
  A) sp² hybridized
  B) sp³ hybridized
  C) sp⁴ hybridized
  D) sp hybridized
  Show Answer
  The correct answer is B .
• Question 355:

  What is the IUPAC name for the following compound? HC$\equiv$CCH${}_3$

  Options:
  A) Acetylene
  B) Methyl acetylene
  C) Butanol
  D) Decanoic acid
  Show Answer
  The correct answer is B .
• Question 356:

  What is the principal ore of iron, from which iron is extracted?

  Options:
  A) Calcite
  B) Bauxite
  C) Magnetite
  D) Hematite
  Show Answer
  The correct answer is D .
• Question 357: An isotope has an atomic number of 15 and a mass number of 31. The number of proton it contains is Options:
  A) 16
  B) 15
  C) 31
  D) 46
  Show Answer
  The correct answer is B .
• Question 358: The gas that can best be collected by downward displacement of air is Options:
  A) Chlorine
  B) Sulphur (IV) oxide
  C) Ammonia
  D) Carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 359: The purest from of iron which contains only about 0.1% carbon is Options:
  A) pig iron
  B) wrough iron
  C) cast iron
  D) iron pyrite
  Show Answer
  The correct answer is B .
• Question 360: 1.00g of mixture of calcium carbonate and calcium oxide liberated 0.33g of carbon dioxide on strong heating. The percentage of calcium oxide in the mixture is? (Ca = 40, C = 12, O = 16) Options:
  A) 5
  B) 15
  C) 25
  D) 35
  E) 50
  Show Answer
  The correct answer is C .