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:

  Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V).
  [Ca = 40, N = 14, O = 16]

  Options:
  A) 8.5%
  B) 13.1%
  C) 17.1%
  D) 27.6%
  Show Answer
  The correct answer is C .
• Question 2: Water molecule can be ligands especially when they are bonded to Options:
  A) alkaline earth metals
  B) alkali metals
  C) transition metals
  D) group VII elements
  Show Answer
  The correct answer is C .
• Question 3: The gasification of coke is used for the manufacture of Options:
  A) producer gas
  B) natural gas
  C) synthetic gas
  D) industrial gas
  E) artificial gas
  Show Answer
  The correct answer is A .
• Question 4: An anhydride is an oxide of non-mental? Options:
  A) which will not dissolve in water
  B) whose solution in water has a pH greater than 7
  C) whose solution in water has a pH less than 7
  D) whose solution in water has a pH of 7
  Show Answer
  The correct answer is C .
• Question 5: Iron is often galvanized in order to Options:
  A) make it more malleable
  B) remove the impurities in it
  C) protect it against corrosion
  D) render it passive
  Show Answer
  The correct answer is C .
• Question 6:

  Elements X and Y have electronic configurations 1s${}^2$2s${}^2$2p${}^4$ and 1s${}^2$2s${}^2$2p${}^6$3s${}^2$3p${}^1$ respectively. When they combine, the formula of the compound formed is

  Options:
  A) XY
  B) X${}_2$Y
  C) Y${}_2$X${}_3$
  D) X${}_2$Y${}_3$
  Show Answer
  The correct answer is C .
• Question 7:

  Which quantum divides shells into orbitals?

  Options:
  A) Spin
  B) Principal
  C) Azimuthal
  D) Magnetic
  Show Answer
  The correct answer is C .
• Question 8: The mass of an atom is determined by Options:
  A) its ionization potential
  B) its electrochemical potential
  C) the number of protons and electrons
  D) the number of neutrons and protons
  E) the number of neutrons and electrons
  Show Answer
  The correct answer is D .
• Question 9: What process would coal undergo to give coal gas, coal tar, ammoniacal liquor and coke? Options:
  A) Steam distillation
  B) Destructive distillation
  C) Liquefaction
  D) Hydrolysis
  Show Answer
  The correct answer is B .
• Question 10: SO₃ is NOT directly dissolved in water in the preparation of H₂SO₄ by the contact process because? Options:
  A) the reaction between SO₃ and water is violently exothermic
  B) acid is usually added to water and never water to acid
  C) SO₃ does not dissolve in water readily
  D) SO₃ is an acid gas
  Show Answer
  The correct answer is A .