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 1611: The pH of a solution obtained by mixing 100cm³ of a 0.2M solution of NaOH is? Options:
  A) 1.3
  B) 7.0
  C) 9.7
  D) 12.7
  Show Answer
  The correct answer is D .
• Question 1612: Which of the following statement is false? Options:
  A) Acids react with some metals, liberating hydrogen
  B) Acids react with carbonates, liberating carbondioxide
  C) Acids conduct electricity and are decomposed by the current, liberating hydrogen at the anode
  D) Acids have a sour taste
  E) Acids change the colour of indicators
  Show Answer
  The correct answer is C .
• Question 1613: A solid that absorbs water from he atmosphere and forms an aqueous solution is? Options:
  A) hydrophilic
  B) efforescent
  C) deliquescent
  D) hygroscopic
  Show Answer
  The correct answer is C .
• Question 1614: By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and Options:
  A) potassium nitrate
  B) sand
  C) lead nitrate
  D) sugar (glucose)
  E) starch
  Show Answer
  The correct answer is B .
• Question 1615: 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 1616: The principal constituent of natural gas is Options:
  A) methane
  B) ethane
  C) propane
  D) butane
  Show Answer
  The correct answer is A .
• Question 1617: The relative atomic mass of a naturally occurring lithium consisting of 90% Li and 10% Li is Options:
  A) 6.9
  B) 7.1
  C) 6.2
  D) 6.8
  Show Answer
  The correct answer is C .
• Question 1618: The periodic classification of elements is an arrangement of the elements in order of their Options:
  A) Atomic Weights
  B) Isotopic Weights
  C) Molecular Weights
  D) Atomic Numbers
  E) Atomic Masses
  Show Answer
  The correct answer is D .
• Question 1619: A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone Options:
  A) distillation
  B) sublimation
  C) precipitation
  D) evaporation
  E) decomposition
  Show Answer
  The correct answer is B .
• Question 1620:

  What is the valency of an element with the electronic configuration 2, 8, 7?

  Options:
  A) 7
  B) 1
  C) 2
  D) 3
  Show Answer
  The correct answer is B .