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 751:

  What is the trend for ionization energy across a period in the periodic table?

  Options:
  A) Increases from left to right.
  B) Remains constant
  C) Varies randomly
  D) Decreases from left to right
  Show Answer
  The correct answer is A .
• Question 752:

  What mass of magnesium would be obtained by passing a current of 2 amperes for 2 hours, through molten magnesium chloride?
  [1 faraday = 96500C, Mg = 24]

  Options:
  A) 1.12g
  B) 4.48g
  C) 1.80g
  D) 2.00g
  Show Answer
  The correct answer is C .
• Question 753: A white solid suspected to be lead trioxonitrate (V) zinc trioxocarbonate (IV) or calcium trioxocabonate (IV) was heated strongly. Its residue which was yellow when hot and white when cold is? Options:
  A) lead (II) oxide
  B) calcium oxide
  C) zinc oxide
  D) lead nitrate
  Show Answer
  The correct answer is C .
• Question 754:

  When 10g of sodium hydroxide is dissolved in 1000cm³ of water, the sodium formed is approximately

  [Na = 23, H = 1, O = 16]

  Options:
  A) 0.01 mol dm^-3
  B) 0.10 mol dm^-3
  C) 0.25 mol dm^-3
  D) 0.50 mol dm^-3
  Show Answer
  The correct answer is C .
• Question 755:

  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 756: which of the following metals will show the highest metallic character? Options:
  A) Zinc
  B) Copper
  C) Barium
  D) Calcium
  Show Answer
  The correct answer is D .
• Question 757: The gasification of coke is used for the manufacturing of Options:
  A) producer gas
  B) natural gas
  C) synthetic gas
  D) industrial gas
  Show Answer
  The correct answer is C .
• Question 758:

  Which trace gas in the atmosphere plays a significant role in the greenhouse effect?

  Options:
  A) Oxygen
  B) Argon
  C) Carbon dioxide
  D) Nitrogen
  Show Answer
  The correct answer is C .
• Question 759: The mass number of an atom is? Options:
  A) the number of electrons in the atom
  B) the number of protons in the nucleus of the atom
  C) the number of neutrons in the nucleus of the atom
  D) the sum of numbers of electrons and protons inthe atom
  E) the sum of numbers of proton and neutrons in the nucleus of the atom
  Show Answer
  The correct answer is E .
• Question 760: Alkanols have the general molecular formula Options:
  A) C₁H_2n-2
  B) C₁H_2n-1CHO
  C) C₁H_2n-2OH
  D) C₂H_2n+1OH
  Show Answer
  The correct answer is D .