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 1031:

  A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

  [ M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl${}_2$
  C) MCl${}_3$
  D) M${}_2$Cl${}_6$
  Show Answer
  The correct answer is C .
• Question 1032:

  GAS	CO${}_2$	N${}_2$	O${}_2$
  % BY VOLUME	4	72	24

  The above table shows the compositions of the atmosphere of planet X. Which of these gases are present inhigherpercentages on earth?

  Options:
  A) CO${}_2$ and O${}_2$
  B) N${}_2$ and CO${}_2$
  C) CO${}_2$, O${}_2$ and N${}_2$
  D) O${}_2$ and N${}_2$
  Show Answer
  The correct answer is D .
• Question 1033: When salt loses its water of crystallization to the atmosphere on exposure, the process is said to be Options:
  A) efflorescence
  B) déliquescence
  C) effervescence
  D) fluorescence
  Show Answer
  The correct answer is A .
• Question 1034: The gas that is the most dangerous pollutant to human is Options:
  A) sulphur (IV) oxide
  B) carbon (IV) oxide
  C) nitrogen (II) oxide
  D) hydrogen sulphide
  Show Answer
  The correct answer is D .
• Question 1035: What type of bond exits between an element X with atomic number 12 and Y with atomic number 17? Options:
  A) Electrovalent
  B) Metallic
  C) Covalent
  D) Dative
  Show Answer
  The correct answer is A .
• Question 1036: An increase in the pressure exerted on gas at a constant temperature results in Options:
  A) a decrease in the number of effective collisions
  B) a decrease in volume
  C) an increase in the average intermolecular distance
  D) an increase in volume
  Show Answer
  The correct answer is B .
• Question 1037: The colour of litmus in a neutral medium is Options:
  A) purple
  B) pink
  C) yellow
  D) orange
  Show Answer
  The correct answer is A .
• Question 1038: The exhaust fumes from a garage in a place that uses petrol of high sulphur content are bound to contain? Options:
  A) CO and SO₃
  B) CO and SO₂
  C) CO,SO₂ and SO₃
  D) CO and H₂S
  Show Answer
  The correct answer is B .
• Question 1039: The processes which return carbon (IV) oxide to the atmosphere include Options:
  A) respiration, decay and combustion
  B) photosynthesis, respiration and transpiration
  C) ozone depletion, combustion and decay
  D) photosynthesis, decay and respiration
  Show Answer
  The correct answer is A .
• Question 1040: What properties of duralumin make it more useful than its constituent metals? Options:
  A) It is heavy with a high melting point
  B) It is malleable and has high density
  C) It is strong and light
  D) It is hard and ductile
  Show Answer
  The correct answer is C .