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 1471: The empirical formula of an oxide of nitrogen containing 30.4 per cent of nitrogen is (N=14.0,O=16.0) Options:
  A) N₂O₂
  B) NO
  C) NO₂
  D) N₂O
  E) N₂O₃
  Show Answer
  The correct answer is C .
• Question 1472: Which of the following alkanes has the highest boiling point? Options:
  A) Pentane
  B) Ethane
  C) Propane
  D) Methane
  Show Answer
  The correct answer is A .
• Question 1473:

  According to Charles' law, the volume of a gas becomes zero at

  Options:
  A) 0°C
  B) -100°C
  C) -273°C
  D) -373°C
  Show Answer
  The correct answer is C .
• Question 1474: The oxidation state of manganese in potassium permanganate is Options:
  A) +7
  B) +5
  C) +3
  D) +2
  E) +1
  Show Answer
  The correct answer is A .
• Question 1475: During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?(M = 65, If = 96,500 C per mole of electron) Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 1476: When steam is passed over red-hot carbon, the substances produced are Options:
  A) Hydrogen and trioxocarbonate (IV) acid
  B) Hydrogen, oxygen and carbon (IV) oxide
  C) Hydrogen and carbon (II) oxide
  D) Hydrogen and carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 1477: The constituent of air necessary in the rusting process are Options:
  A) O₂ and H₂O
  B) Ar and CO₂
  C) CO₂ and H₂O
  D) O₂ and CO₂
  Show Answer
  The correct answer is D .
• Question 1478: What properties of duralumin make it more useful than its constituent metals? Options:
  A) It is heavy with a high melting point
  B) It is malleable and has high density
  C) It is strong and light
  D) It is hard and ductile
  Show Answer
  The correct answer is C .
• Question 1479: The maximum number of electrons in the L shell of an atom is Options:
  A) 2
  B) 8
  C) 18
  D) 32
  Show Answer
  The correct answer is B .
• Question 1480: An element Z, contained 90% of ¹⁶₈Z and 10% of Z¹⁸₁₈ its relative atomic mass is? Options:
  A) 16.0
  B) 16.2
  C) 17.0
  D) 17.8
  Show Answer
  The correct answer is B .