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 1771: The reaction between ammonia and ethyl ethanoate produces Options:
  A) propanol and ethanamide
  B) propanol and propanamide
  C) ethanol and propanamide
  D) ethanol and ethanamide
  Show Answer
  The correct answer is D .
• Question 1772:

  Addition of sodium chloride to water to form a solution would lead to?

  Options:
  A) increase in freezing point and increase the boiling point
  B) increase in freezing point and decrease the boiling point
  C) decrease in freezing point and decrease the boiling point
  D) decrease in freezing point and increase the boiling point
  Show Answer
  The correct answer is D .
• Question 1773: A sample of an oxide of mercury weighed 1.00g. When this was heated, oxygen was given off, and 1.00g of mercury metal only was left. What is the formula of the oxide? Options:
  A) Hg₂O
  B) HgO₂
  C) HgO₂
  D) HgO
  E) None of the above
  Show Answer
  The correct answer is E .
• Question 1774: The process of converting linear alkanes to branched chain and cyclic hydrocarbons by heating in the presence of a catalyst to improve the quality of petrol is referred to as Options:
  A) refining
  B) craching
  C) reforming
  D) blending
  Show Answer
  The correct answer is C .
• Question 1775: The atomic number of an element whose cation, X²⁺, has the ground state electronic configuration 1s²2s²2p⁶3s²2p⁶ is? Options:
  A) 16
  B) 18
  C) 20
  D) 22
  E) 24
  Show Answer
  The correct answer is C .
• Question 1776:

  Electrons enter into orbitals in order of increasing energy as exemplified by?

  Options:
  A) 1S${}^2$2S${}^2$2PX${}^2$2py${}^2$2pz${}^0$3s${}^0$
  B) 1S${}^2$2S${}^2$2PX${}^2$2py${}^1$2pz${}^1$3s${}^0$
  C) 1S${}^2$2S${}^2$2PX${}^1$2py${}^1$2pz${}^1$3s${}^1$
  D) 1S${}^2$2S${}^2$2PX${}^2$2py${}^2$2pz${}^0$3s${}^1$
  Show Answer
  The correct answer is B .
• Question 1777: The function of zinc electrode in a galvanic cells is that it Options:
  A) undergoes reduction
  B) serves as the positive electrode
  C) production electons
  D) uses up electrons
  Show Answer
  The correct answer is C .
• Question 1778: The knowledge of half-life can be used to Options:
  A) create an element
  B) detect an element
  C) split an element
  D) irradiate an element
  Show Answer
  The correct answer is A .
• Question 1779: Nitrogen can best be obtained from a mixture over oxygen and nitrogen by passing the mixture over Options:
  A) potassium hydroxide
  B) heated gold
  C) heated magnesium
  D) heated phosphorus
  E) calcium chloride
  Show Answer
  The correct answer is D .
• Question 1780: The shapes of CO${}_2$, H${}_2$O and CH${}_4$ respectively are Options:
  A) bent, linear and tetrahedral
  B) bent, tetrahedral and linear
  C) linear, bent and tetrahedral
  D) tetrahedral, linear and bent
  Show Answer
  The correct answer is C .