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 621: In the reaction Fe + Cu²⁺ $\to$ Fe²⁺ + Cu,iron displaces copper ions to from copper. This is due to the fact that Options:
  A) irn is in the metallic from while the copper is in the ionic from
  B) the atomic weight of copper is greater than that of iron
  C) copper is greater than iron
  D) copper metal has more electrons than iron metal
  E) iron is higher in the electrochemical series than copper
  Show Answer
  The correct answer is E .
• Question 622: The four classes of hydrocarbons are? Options:
  A) ethane, ethene, ethyne and benzene
  B) alkanes, alkenes, alkynes and aromatics
  C) alkanes, alkenes, alkynes and benzene
  D) methane, ethane , propane and butane
  Show Answer
  The correct answer is B .
• Question 623: Group VII elements are Options:
  A) monoatmic
  B) good oxidizing agents
  C) highly electropositive
  D) electron donors
  Show Answer
  The correct answer is B .
• Question 624: Consecutive members of an alkane homologous serires differ by Options:
  A) CH
  B) CH₂
  C) CH₃
  D) C_nH_n
  E) C_nH
  Show Answer
  The correct answer is B .
• Question 625: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 626: If a gas occupies a container of volume 146 cm³ at 18°C and 0.97`atm, its volume 146cm³ at s.t.p is? Options:
  A) 133
  B) 146
  C) 266
  D) 292
  Show Answer
  The correct answer is A .
• Question 627: The iron (III) oxide impurity in bauxite can be removed by? Options:
  A) Fractional crystallization in acid solution
  B) dissolution in sodium hydroxide and filtration
  C) extraction with concentrated ammonia and reprecipitation
  D) electroysis of molten mixture
  Show Answer
  The correct answer is B .
• Question 628:

  Consider the reaction

  A${}_{(s)}$ + 2B${}_{(g)}$ → 2C${}_{(aq)}$ + D${}_{(g)}$

  What will be the effect of a decrease in pressure on the reaction?

  Options:
  A) the equilibrium will shift
  B) rate of forward reaction will increase
  C) rate of backward reaction will increase
  D) rates of forward and backward reaction are not affected
  Show Answer
  The correct answer is B .
• Question 629: Which of the following is acceptable as the organic product of the reaction of ethanoic acid and ethanol with an acid catalyst? Options:
  A) Ethyl ethanoate
  B) Methyl ethanoate
  C) Ethyl methyl ketone
  D) Butanol
  E) None
  Show Answer
  The correct answer is A .
• Question 630: MnO^-₄ + 8H⁺ + ne → Mn⁺⁺ + 4H₂O. Which is the value of n in the reaction above? Options:
  A) 2
  B) 3
  C) 4
  D) 5
  Show Answer
  The correct answer is D .