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 1961:

  

  Consider the solubility curves of three salts X, Y and Z given in the diagram. If each solution of the salt contains 200 g, and is heated to 100°C, which solution or solutions will deposit 100 g of the solute when suddenly cooled to 0°C?

  Options:
  A) X only
  B) Y only
  C) Z only
  D) X and Z
  E) Y and Z
  Show Answer
  The correct answer is E .
• Question 1962:

  5SO_2(g) + 2KMnO_4(aq) + 2H₂O_(l) → K₂SO₄ + 2MnSO_4(aq) + 2H₂SO_4(aq)

  In the reaction above, the products give a

  Options:
  A) purple solution
  B) purple precipitate
  C) colourless precipitate
  D) colourless solution
  Show Answer
  The correct answer is D .
• Question 1963:

  Sulphur exists in six forms in the solid state. This property is known as

  Options:
  A) Isomerism
  B) Allotropy
  C) Isotopy
  D) Isomorphism
  Show Answer
  The correct answer is B .
• Question 1964:

  ZnO_(s) + CO_(g) → Zn_(s) + CO_2(g)

  In the reaction above, Zinc has been

  Options:
  A) decomposed
  B) displaced
  C) oxidized
  D) reduced
  Show Answer
  The correct answer is D .
• Question 1965:

  The number of electrons in the valence shell of an element of atomic number 14 is?

  Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is D .
• Question 1966:

  One of the following is not a physical property of monosaccharides?

  Options:
  A) Monosaccharides get charred when heated
  B) Monosaccharides are water-soluble, sweet substances
  C) They are highly vital to the exploration of metals
  D) They can be reduced to sugar alcohols
  Show Answer
  The correct answer is C .
• Question 1967:

  Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

  Options:
  A) Ionic bonding
  B) Hydrogen bonding
  C) Covalent bonding
  D) Metallic bonding
  Show Answer
  The correct answer is A .
• Question 1968: For iron to rust, there should be present? Options:
  A) oxygen
  B) moisture
  C) carbondioxide
  D) oxygen and moisture
  E) oxygen, moisture and carbondioxide
  Show Answer
  The correct answer is D .
• Question 1969:

  

  It can be deduced that the rate of the reaction

  Options:
  A) for bath l is higher than path ll
  B) for path ll is higher than path l
  C) is the same for both paths at all temperatures
  D) depends on the values of both x and y at all pressures
  Show Answer
  The correct answer is B .
• Question 1970: The mass number of an atom is? Options:
  A) the number of electrons in the atom
  B) the number of protons in the nucleus of the atom
  C) the number of neutrons in the nucleus of the atom
  D) the sum of numbers of electrons and protons inthe atom
  E) the sum of numbers of proton and neutrons in the nucleus of the atom
  Show Answer
  The correct answer is E .