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 221: Which of the following happens during the electrolysis of molten sodium chloride? Options:
  A) Sodium ion loses an electron
  B) Chlorine atom gains an electron
  C) Chlorine ion gains an electron
  D) Sodium ion is oxidized
  E) Chloride ion is oxidized
  Show Answer
  The correct answer is E .
• Question 222: Calculate the mass of copper deposited when a current of 0.5 ampere was passed through a solution of copper(II) chloride for 45 minutes in an electrolytic cell. [Cu = 64, F = 96500Cmol^-1] Options:
  A) 0.300g
  B) 0.250g
  C) 0.2242g
  D) 0.448g
  Show Answer
  The correct answer is D .
• Question 223:

  The mass of one Avogadro number of helium atoms is?

  Options:
  A) 1.00gram
  B) 4.00gram
  C) 8.00gram
  D) 6.00gram
  Show Answer
  The correct answer is B .
• Question 224: The electron configuration of two elements with similar chemical properties are represented by? Options:
  A) 1s²2s²2p⁵ and 1s²2s²2p⁴
  B) 1s²2s²2p⁴ and 1s²2s²2p⁶3s¹
  C) 1s²2s²2p⁶3s¹ and 1s²2s¹
  D) 1s²2s²2p⁴ and 1s²2s¹
  Show Answer
  The correct answer is C .
• Question 225:

  The molar enthalpy change accompanying the removal of an electron from a gas phase atom orion in its ground state is called?

  Options:
  A) Electron gain enthalpy
  B) Ionization enthalpy
  C) Enthalpy change
  D) Enthalpic gas removal
  Show Answer
  The correct answer is B .
• Question 226: The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an? Options:
  A) alkanoate
  B) alkaene
  C) alkanol
  D) alkane
  Show Answer
  The correct answer is C .
• Question 227:

  What is the IUPAC name for the compound CCl${}_4$?

  Options:
  A) Tetrahydrochloride
  B) Tetrachloromethane
  C) Carbon tetrachloride
  D) Chloroform
  Show Answer
  The correct answer is B .
• Question 228:

  A solution contains 20g of solute in 180g of solvent. If the solvent is water, what is the concentration of the solution in terms of mass by mass percentage

  Options:
  A) 11.%
  B) 22.2%
  C) 10%
  D) 20%
  Show Answer
  The correct answer is C .
• Question 229: Copper and silver metals are commonly use as coin because they are Options:
  A) easily reduced
  B) not easily reduced
  C) easily oxidized
  D) not easily oxidized
  Show Answer
  The correct answer is D .
• Question 230: The process of converting starch to ethanol is Options:
  A) cracking
  B) distillation
  C) fermentation
  D) oxidation
  Show Answer
  The correct answer is C .