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 981:

  If one of the following oxides is heated with hydrogen or carbon using a bunsen burner. it is not reduced to the metal, Which one is it?

  Options:
  A) lead oxide
  B) Magnesium oxide
  C) Copper oxide
  D) Tin oxide
  Show Answer
  The correct answer is B .
• Question 982: Equal moles of ethyne and hydrogen iodide react to give Options:
  A) CH₂ = CH₂
  B) CH₂ - CHI
  C) CH₃ - CI
  D) CH₂ = CHI
  Show Answer
  The correct answer is D .
• Question 983: 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 984:

  What is the empirical formula of a compound containing 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?

  Options:
  A) C${}_4$H${}_8$O${}_4$
  B) CH${}_2$O
  C) C${}_2$H${}_4$O${}_2$
  D) C${}_3$H${}_6$O${}_3$
  Show Answer
  The correct answer is B .
• Question 985: A mixture is different from a compound because Options:
  A) the properties of a compound are those of its individual constituents while those of a mixture differ from its constituents
  B) a mixture is always homogeneous while a compound is not
  C) the constituent of a compound are chemically bound together while those of a mixture are not
  D) a mixture can be represented by a chemical formula while a compound cannot
  Show Answer
  The correct answer is C .
• Question 986: When chlorine is passed into water and subsequently exposed to sunlight, the gas evolved is? Options:
  A) HCl
  B) HOCl
  C) O₂
  D) Cl₂O
  Show Answer
  The correct answer is C .
• Question 987: The relatively high boiling points of alkanols are due to? Options:
  A) ionic bonding
  B) aromatic character
  C) covalent bonding
  D) hydrogen bonding
  Show Answer
  The correct answer is D .
• Question 988:

  A sample of any of the following substances disappearsafter some time when exposed to air like camphor, naphthalene, or dry ice. This phenomenon is called?

  Options:
  A) Sublimation
  B) Evaporation
  C) Diffusion
  D) Radiation
  Show Answer
  The correct answer is A .
• Question 989:

  

  Which of the five atoms can be described by the following properties: Relative atomic mass is greater than 30 but less than 40, it has odd atomic number and forms a unipositive ion in solution?

  Options:
  A) T
  B) W
  C) X
  D) Y
  E) Z
  Show Answer
  The correct answer is D .
• Question 990: If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form? Options:
  A) Dative
  B) Covalent
  C) Lonic
  D) Metallic
  Show Answer
  The correct answer is C .