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 691:

  Sulphur exists in six forms in the solid state. This property is known as

  Options:
  A) Isomerism
  B) Allotropy
  C) Isotopy
  D) Isomorphism
  Show Answer
  The correct answer is B .
• Question 692: Chlorination of water for town supply is carried out to Options:
  A) make the water colourless
  B) remove germs from the water
  C) make the water tastedful
  D) remove odour from the water
  Show Answer
  The correct answer is B .
• Question 693: In the oil drop experiment, Millikan determined the? Options:
  A) charge to mass ratio of the electron
  B) mass of the electron
  C) charge of the electron
  D) mass of the proton
  Show Answer
  The correct answer is C .
• Question 694:

  What is the chemical name for the compound CuCO${}_3$?

  Options:
  A) Copper (iii) carbonate
  B) Copper (ii) carbonate
  C) Copper (i) carbonate
  D) Copper
  Show Answer
  The correct answer is B .
• Question 695: The solubilites of different solutes in a given solvent can be compared by Options:
  A) plotting their solubility curves on separete axes
  B) plotting their solubility curves on the same axes
  C) plotting some of the solubility curves on the x-axis and others on the y-axis
  D) plotting their solubility curves on the x-axis only
  Show Answer
  The correct answer is B .
• Question 696:

  What happens to the value of the equilibrium constant (Kc) for a reaction if the reaction is reversed?

  Options:
  A) It becomes zero
  B) It becomes negative
  C) It remains the same
  D) It becomes the reciprocal of the original value
  Show Answer
  The correct answer is D .
• Question 697:

  

  Use the graph above to answer this question.

  A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section OP suggests that X is in the

  Options:
  A) liquid sate
  B) solid/liquid state
  C) solid state
  D) gaseous state
  Show Answer
  The correct answer is A .
• Question 698: When air is compressed? Options:
  A) its density decreases
  B) it solidifies
  C) its temperature decreases
  D) its temperature increases
  E) its temperature remains unchanged
  Show Answer
  The correct answer is C .
• Question 699: PCL5(g)= PCL3(g) + Cl2(g)In the reaction above, a decrease in pressure will Options:
  A) Decelerate the reaction
  B) Increase yield of Pcl3
  C) Increase the yield of Pcl5
  D) Accurate the reaction
  Show Answer
  The correct answer is B .
• Question 700: Alkanals can be differentiated from alkanones by reaction with? Options:
  A) 2,4-dinitrophenylhydrazine
  B) hydrogen cyanide
  C) sodium hydrogen sulphite
  D) Tollen's reagent
  Show Answer
  The correct answer is D .