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:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
  Show Answer
  The correct answer is B .
• Question 2: Hydrogen sulphide gas can act as Options:
  A) an oxidizing agent
  B) a dehydrating agent
  C) a bleaching agent
  D) a precipitating agent
  Show Answer
  The correct answer is D .
• Question 3: Which of the following compounds is the best possible anti-knock agent for petrol? Options:
  A) (CH₃)₂CH - CH(CH₃)CH₂CH₃
  B) CH₃CH₂(CH₃)CHCH₂CH₂CH₃
  C) CH₃CH₂(CH₃)CHCH₂CH₂CH₃
  D) (CH₃)₃C - CH₂CH₂CH₃
  Show Answer
  The correct answer is A .
• Question 4: An amphoteric oxide is an? Options:
  A) amorphous oxide of a metal
  B) amorphous oxide of a non-mental
  C) oxide that is insoluble in water
  D) oxide that behaves both as a base as well as an acid
  E) oxide that loses its oxygen on sublimation
  Show Answer
  The correct answer is D .
• Question 5: Bronze is preferred to copper in the making of medals because it Options:
  A) is stronger
  B) can withstand low temperature
  C) is lighter
  D) has low tensile strength
  Show Answer
  The correct answer is A .
• Question 6: The process that requires the use of hardwater in its operation is Options:
  A) Tanning
  B) Bottling
  C) Laundry
  D) Dyeing
  Show Answer
  The correct answer is B .
• Question 7: 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 8:

  What are the possible oxidation numbers of an element if its atomic number is 17?

  Options:
  A) -1 and 7
  B) -1 and 6
  C) -3 and 5
  D) -2 and 6
  Show Answer
  The correct answer is A .
• Question 9: Which of the following compounds is NOT formed by the action of chlorine on methane? Options:
  A) CH₃CI
  B) C₂H₅CI
  C) CH₂CI₂
  D) CHCI₃
  Show Answer
  The correct answer is B .
• Question 10:

  The part of the total energy of a system that accounts for the useful work done in a system is known as

  Options:
  A) Enthalpy change
  B) None of the above
  C) Gibb's free energy
  D) Entropy
  Show Answer
  The correct answer is C .