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 881: Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes. Options:
  A) 2.7
  B) 5.4
  C) 10.8
  D) 21.7
  Show Answer
  The correct answer is B .
• Question 882: An oxide XO₂ has a vapour density of 32. What is the atomic mass of X? Options:
  A) 32
  B) 20
  C) 14
  D) 12
  Show Answer
  The correct answer is A .
• Question 883:

  

  Which of the curves shown in the figure given represents the relationships between the volume(V) and pressure(P) of an ideal gas at constant temperature?

  Options:
  A) 1
  B) 2
  C) 3
  D) 4
  E) 1 and 3
  Show Answer
  The correct answer is C .
• Question 884:

  Which one of the following is not a mixture?

  Options:
  A) Air
  B) Mercury
  C) Milk
  D) Cement
  Show Answer
  The correct answer is B .
• Question 885:

  The process or act of extracting a metal from its ore and refining it is called?

  Options:
  A) Extraction
  B) Metal mining
  C) Mettallurgy
  D) Prospecting
  Show Answer
  The correct answer is C .
• Question 886: Which of the following will react further with oxygen to form higher oxide? Options:
  A) NO and H₂O
  B) CO and CO₂
  C) SO₂ and NO
  D) CO₂ and H₂O
  Show Answer
  The correct answer is C .
• Question 887:

  

  The diagram represents

  Options:
  A) A spontaneous reaction
  B) An exothermic reaction
  C) A non-spontaneous
  D) An endothermic reaction
  Show Answer
  The correct answer is C .
• Question 888:

  Which of the following is a non-metal that remains liquid at room temperature?

  Options:
  A) Chlorine
  B) Phosphorus
  C) Bromine
  D) Helium
  Show Answer
  The correct answer is C .
• Question 889: The synthetic detergents are preferred to soap for laundry using hard water because? Options:
  A) detergents are water soluble while soap is not
  B) the calcium salts of detergents are water soluble
  C) the magnesium salt of soap is soluble in hard water
  D) soap does not have a hydrocarbon terminal chain
  Show Answer
  The correct answer is B .
• Question 890: How many structural isomers of chlorobutane are possible? Options:
  A) 4
  B) 3
  C) 2
  D) 1
  Show Answer
  The correct answer is A .