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 41: The atom of an element X is represented as _z^yX. The basic chemical properties of X depends on the value of Options:
  A) Y
  B) Z
  C) Y - Z
  D) Z - Y
  Show Answer
  The correct answer is B .
• Question 42: Detergents are more advantageous than soaps in hard water districts because Options:
  A) on treatment with hard water they either form soluble calcium salts or do not react with calcium ion
  B) on treatment with hard water they form soluble calcium salts
  C) on treatment with hard water they form sodium salts
  D) on treatment with hard water they are converted into soaps
  E) on treatment with hard water they form more lather than soaps does
  Show Answer
  The correct answer is A .
• Question 43:

  220g of carbon dioxide contains ----- moles

  Options:
  A) 5
  B) 6
  C) 3
  D) 4
  Show Answer
  The correct answer is A .
• Question 44: A pair of compounds that can be used to generate a gas which has physiological effect on human beings is Options:
  A) sodium trioxonitrate (V) and calcium chloride
  B) sodium dioxonitrate (III) and ammonium chloride
  C) sodium trioxonitrate (V) and ammonium chloride
  D) sodium dioxonitrate (III) and potassium chloride
  Show Answer
  The correct answer is A .
• Question 45:

  

  Choose the correct option from the graph above.

  3Fe_(S) + 4H₂O_(g) ⇌ Fe₃O_4(s) + 4H_2(g). The equilibrium constant, K, of the reaction above is represented as

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 46:

  Which of the following mixtures is an example of a colloid?

  Options:
  A) Milk
  B) Orange juice
  C) Saltwater
  D) Sugar dissolved in water
  Show Answer
  The correct answer is A .
• Question 47: A chemical reaction is always associated with Options:
  A) an increase in the composition of one of the substance
  B) a change in the volume of the reactants
  C) a change in the nature of the reactants
  D) the formation of new substance
  Show Answer
  The correct answer is D .
• Question 48: Metalliods are also referred to as Options:
  A) semi-metals
  B) metals
  C) colliods
  D) non-metals
  Show Answer
  The correct answer is A .
• Question 49:

  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 50: The hydrocarbon that burns in air with a sooty flames is Options:
  A) C₂H₆
  B) C₃H₈
  C) C₄H₁₀
  D) C₆H₆
  Show Answer
  The correct answer is D .