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 531: Rare gases are suitable because they Options:
  A) are monoatomic
  B) form ions easily
  C) have duplet or octet electronic configuration in the outermost shells in their atoms
  D) are volatile gases
  Show Answer
  The correct answer is C .
• Question 532: An anhydride is Options:
  A) a compound wich has no water of crystallization
  B) an oxide whose solution in water has a PH greater than 7
  C) an oxide whose solution in water has a PH less than 7
  D) an oxide that has hydrogen atoms
  E) an amphoteric oxide
  Show Answer
  The correct answer is C .
• Question 533:

  

  Changes in the physical in the scheme above.The letter X,Y and Z respectively represent

  Options:
  A) sublimation, condensation and freezing
  B) sublimation, vapourization and solidification
  C) freezing, condensation and sublimation
  D) evaporation, liquefaction and solidification
  Show Answer
  The correct answer is A .
• Question 534: When a piece of charcoal enclosed in a cylinder containing air is ignited Options:
  A) the toatl volume of air is increased
  B) the relative amount of oxygen present is increased
  C) the relative amount of nitrogen present is decreased
  D) the relative amount of carbondioxide present is increased
  E) the ratio of oxygen to nitrogen in the system is increased
  Show Answer
  The correct answer is D .
• Question 535:

  A chemical process in which there is a gain of electrons is known as?

  Options:
  A) Sublimation
  B) Reduction
  C) Oxidation
  D) Distillation
  Show Answer
  The correct answer is B .
• Question 536:

  Hard water is water with high concentrations of dissolved ions, in particular calcium and

  Options:
  A) magnesium ions
  B) nitrogen ions
  C) phosporus ions
  D) helium ions
  Show Answer
  The correct answer is A .
• Question 537:

  

  In the diagram above which of the cures illustrates Arrhenius' law?

  Options:
  A) Y
  B) Z
  C) R
  D) X
  Show Answer
  The correct answer is D .
• Question 538: Which of the following metals does NOT form a stable trioxocarbonate (IV)? Options:
  A) Fe
  B) Al
  C) Zn
  D) Pb
  E) none of the options is correct
  Show Answer
  The correct answer is E .
• Question 539:

  What number of moles of Cu ²⁺ will be deposited by 360 coulombs of electricity?

  [f = 96500 C mol ^-1]

  Options:
  A) 5.36 x 10 ^-4 mole
  B) 1. 87 x 10 10 ^-3 mole
  C) 9. 35 x 10 ^-4 mole
  D) 3. 73 x 10 ^-3
  Show Answer
  The correct answer is B .
• Question 540: A gas that will turn orange potassium heptaoxodichromate (lV) solution to clear green is? Options:
  A) sulphur (ii) oxide
  B) hydrogen sulphide
  C) sulphide (lV) oxide
  D) hydrogen chloride
  Show Answer
  The correct answer is A .