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: When excess ethanol is heated to 145 ^oC in the presence of concentrated sulphuric acid, the product is Options:
  A) diethyl ether
  B) ethyne
  C) diethyl sulphate
  D) acetone
  E) ethanoic acid
  Show Answer
  The correct answer is A .
• Question 2:

  Which of the following is a physical change?

  Options:
  A) Exposing white phosphorus to air
  B) Burning kerosene
  C) Dissolving calcium in water
  D) Freezing ice cream
  Show Answer
  The correct answer is D .
• Question 3:

  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 4:

  Addition of charcoal to the filter bed of sand during water treatment for township supply is to?

  Options:
  A) prevent goiter
  B) prevent tooth decay
  C) remove odour
  D) kill germs
  Show Answer
  The correct answer is C .
• Question 5: Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled Options:
  A) S orbital
  B) P orbital
  C) D orbital
  D) F orbital
  Show Answer
  The correct answer is C .
• Question 6: A compound contains 40.0% C, 6.7% H 53.3% O. If the molecular mass of the compound is 180, its molecular formula is [C =12, H =1,O] Options:
  A) CH₂O
  B) C₃H₆O₃
  C) C₆H₆O₃
  D) C₆H₁₂O₆
  Show Answer
  The correct answer is D .
• Question 7:

  An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?

  Options:
  A) Alkene
  B) Alkanal
  C) Alkanone
  D) Alkanoic Acid
  Show Answer
  The correct answer is A .
• Question 8: The partial pressure of oxygen in a sample of air is 452mmHg and the total pressure is 780mmHg. What is the mole fraction of oxygen? Options:
  A) 0.203
  B) 0.579
  C) 2.060
  D) 5.790
  Show Answer
  The correct answer is B .
• Question 9:

  Beryllium and Aluminium have similar properties because they

  Options:
  A) are both metals
  B) belong to the same group
  C) belong to the same period
  D) are positioned diagonally to each other
  Show Answer
  The correct answer is D .
• Question 10: Which of the following is NOT true of metals? Options:
  A) They are good conductors of electricity
  B) They ionize by electron loss
  C) Their oxides are acidic
  D) They have high melting points
  Show Answer
  The correct answer is C .