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 481: A compound commonly used for sterilization and preservation of specimens and food is Options:
  A) ethanol
  B) benzene
  C) ether
  D) ammonia
  Show Answer
  The correct answer is A .
• Question 482: An effect of thermal pollution on water bodies is that the Options:
  A) volume of water reduces
  B) volume of chemical waste increase
  C) level of oxides of nitrogen increase
  D) level of oxygen reduces
  Show Answer
  The correct answer is D .
• Question 483:

  When a substance is oxidized, it

  Options:
  A) Loses electrons
  B) Gains oxygen atoms
  C) Gains electrons
  D) Loses protons (H+ ions)
  Show Answer
  The correct answer is A .
• Question 484: Which of these statements is TRUE about carbon (IV) oxide? Options:
  A) it supports combustion
  B) It is strongly acidic in water
  C) It is very soluble in water
  D) It supports the buring of magnesium to produce magnesium oxide
  Show Answer
  The correct answer is C .
• Question 485: The general formula of an alkyl halide (where X represents the halide) is? Options:
  A) C_nH_2n2X
  B) C_nH_2n + ₁X
  C) C_nH_2n + ₂X
  D) C_nH_2nX
  Show Answer
  The correct answer is B .
• Question 486: 2 - methyl propan -2- ol is an example of a Options:
  A) primary alkanol
  B) secondary alkanol
  C) tertiary alkanol
  D) quartenary alkanol
  Show Answer
  The correct answer is C .
• Question 487: The principle of column chromatography is based on the ability of the constituents to Options:
  A) move at different speeds in the column
  B) dissolve in each other in the column
  C) react with the solvent in the column
  D) react with each other in the column
  Show Answer
  The correct answer is A .
• Question 488: Which of the following is physical change? Options:
  A) Burning kerosene
  B) Freezing ice cream
  C) Exposing white phosphorus
  D) Dissolving calcium in water
  Show Answer
  The correct answer is B .
• Question 489: An efflorescent compound is a substance that? Options:
  A) absorbs water froom the air without dissolving in it
  B) is capable of giving off coloured luminosity
  C) gives out water to the atmosphere
  D) absorbs water from the air and dissolves in it
  E) gives out its water of crystallization on heating
  Show Answer
  The correct answer is C .
• Question 490:

  The volume occupied by 1.58g of a gas at S.T.P is 500cm${}^3$. What is the relative molecular mass of the gas?  [ G.M.V at S.T.P = 22.4dm${}^3$ ]

  Options:
  A) 28
  B) 32
  C) 44
  D) 71
  Show Answer
  The correct answer is D .