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 71: Mineral acids are usually added to commercial hydrogen peroxide to Options:
  A) oxidize it
  B) decompose it
  C) minimize its decomposition
  D) reduce it to water and oxygen
  Show Answer
  The correct answer is C .
• Question 72: During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?(M = 65, If = 96,500 C per mole of electron) Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 73: A heterogenous mixture can be defined as any mixture Options:
  A) of a solute nd a solvent
  B) whose cmposition is uniform
  C) whose composition is not uniform
  D) formed by solids and liquids
  Show Answer
  The correct answer is C .
• Question 74: The iron (III) oxide impurity in bauxite can be removed by? Options:
  A) Fractional crystallization in acid solution
  B) dissolution in sodium hydroxide and filtration
  C) extraction with concentrated ammonia and reprecipitation
  D) electroysis of molten mixture
  Show Answer
  The correct answer is B .
• Question 75:

  .....................P....Q.....R......S

  Proton..............13....16....17.....19

  Electron............13....16....17.....19

  Neutron.............14....16....35.....20Which of the four atoms P,q,R and in S in the above data can be described by the following properties relative atomic mass is greater than 30 but less than 40; it has an odd atomic number and forms a unipositive ion in solution?

  Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is D .
• Question 76: Which of the following compounds will burn with a brick-red colour in a non-luminous Bunsen flame? Options:
  A) LiCI
  B) NaCl
  C) CaCl₂
  D) MgCl₂
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  The correct answer is C .
• Question 77: The repeating unit in natural rubber is Options:
  A) alkyne
  B) isoprene
  C) n-propene
  D) peoprene
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  The correct answer is B .
• Question 78:

  The velocity, V of a gas is related to its mass, M by (k = proportionality constant)

  Options:
  A) V = $\frac{k}{M}$
  B) V = $\frac{k}{M^{\frac{1}{2}}}$
  C) V = $k{M}^2$
  D) V = $(\frac{k}{M}{)}^{\frac{1}{2}}$
  Show Answer
  The correct answer is B .
• Question 79: If the relative molecular mass of an element is not a whole number, it can be deduced that the element is Options:
  A) Naturally radioactive
  B) abundant in nature
  C) a transition metal
  D) an isotopic mixture
  Show Answer
  The correct answer is D .
• Question 80: The noble gases owe their inactivity to Options:
  A) Octet configuration
  B) Cyclic shape
  C) Hexagonal shape
  D) Obtuse configuration
  Show Answer
  The correct answer is A .