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 41:

  An element having the atomic number 17 will resemble which of the following elements having atomic number as given below?

  Options:
  A) 33
  B) 35
  C) 18
  D) 19
  Show Answer
  The correct answer is B .
• Question 42:

  An element Z contains 80% of ${}_8^{16}$Z and 20% of ${}_8^{18}$Z. Its relative atomic mass is

  Options:
  A) 16.2
  B) 17.6
  C) 16.0
  D) 16.4
  Show Answer
  The correct answer is D .
• Question 43:

  Helium is used in observation of ballons because it is?

  Options:
  A) Light and combustible
  B) light and non-combustible
  C) heavy and combustible
  D) heavy and non-combustible
  Show Answer
  The correct answer is B .
• Question 44:

  

  Use the diagram above to answer this question.

  Which of the following structural formula is NOT isomeric with the others?

  Options:
  A) A
  B) B
  C) C
  D) D
  E) E
  Show Answer
  The correct answer is D .
• Question 45: Tin is unaffected by air at ordinary temperature due to its Options:
  A) Low melting point
  B) Weak electropositive character
  C) High boiling point
  D) White lustrous appearance
  Show Answer
  The correct answer is A .
• Question 46: what is the pH of 0.00lmoldm³ solution of sodium hydroxide Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 47: The number of isomers formed by C₆H₁₄ is Options:
  A) 4
  B) 5
  C) 2
  D) 3
  Show Answer
  The correct answer is B .
• Question 48: 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 49:

  220g of carbon dioxide contains ----- moles

  Options:
  A) 5
  B) 6
  C) 3
  D) 4
  Show Answer
  The correct answer is A .
• Question 50: In the electrolysis of a concentrated solution of sodium chloride using electrodes, which of the following ions are discharged at the cathode and anode respectively? Options:
  A) Na⁺ and Cl^-
  B) Na⁺ and OH^-
  C) H⁺ and OH^-
  D) H⁺ and Cl^-
  Show Answer
  The correct answer is D .