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 71:

  Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.

  The relative abundance of the isotope of mass number 37 is?

  Options:
  A) 20
  B) 25
  C) 50
  D) 75
  Show Answer
  The correct answer is B .
• Question 72: Which of the noble gases has the greatest ionization energy Options:
  A) He
  B) Xe
  C) Ar
  D) Rr
  Show Answer
  The correct answer is A .
• Question 73:

  Why is water often referred to as the "universal solvent"?

  Options:
  A) Water is the most abundant substance on Earth
  B) Water is essential for all living organisms.
  C) Water is involved in many chemical reactions
  D) Water can dissolve a wide variety of substances due to its polar nature
  Show Answer
  The correct answer is D .
• Question 74:

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  [ F = 96 5000 C mol^-1 ]

  Options:
  A) 24 125 coulombs
  B) 48 250 coulombs
  C) 72 375 coulombs
  D) 96 500 coulombs
  Show Answer
  The correct answer is B .
• Question 75:

  How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?

  Options:
  A) none
  B) 6
  C) 7
  D) 8
  Show Answer
  The correct answer is A .
• Question 76: Which volume of 0.5 M H ₂SO₄ will exactly neutralize 20 cm ³ of 0.1 M NaOH solution? Options:
  A) 2.0 cm ³
  B) 5.0 cm ³
  C) 6.8 cm ³
  D) 8.3 cm ³
  E) 10.4 cm ³
  Show Answer
  The correct answer is A .
• Question 77: What is the pH of 0.001 mol dm^-3 solution of sodium hydroxide Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 78: In an electrochemical cell, polarization is caused by Options:
  A) Oxygen
  B) Hydrogen
  C) Tetraoxosulphate(IV) acid
  D) Chlorine
  Show Answer
  The correct answer is B .
• Question 79:

  Which of the following is a common property of non-metals?

  Options:
  A) Exist as solids at room temperature
  B) Tend to gain electrons in chemical reactions
  C) High thermal conductivity
  D) Readily form cations in chemical reactions
  Show Answer
  The correct answer is B .
• Question 80: How many cations will be produced from a solution of potassium aluminium tetraoxosulphate (VI)? Options:
  A) 3
  B) 4
  C) 1
  D) 2
  Show Answer
  The correct answer is D .