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 1851: The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ? Options:
  A) 45
  B) 55
  C) 80
  D) 100
  Show Answer
  The correct answer is B .
• Question 1852: The normal boiling point of a liquid is defined as Options:
  A) the temperature at which its vapour pressure equals the atmospheric pressure
  B) the temperature at which bubbles begin to form
  C) the temperature at which the vapour pressure equals 1 temperature
  D) the temperature at which the rate of condensation of vapour equals the rate of vaporisation of the liquid
  E) the temperature at which the space above the liquid is saturated
  Show Answer
  The correct answer is C .
• Question 1853: A common characteristic shared by iron and aluminium is that both? Options:
  A) are extracted by reduction methods
  B) form only basic oxides
  C) show oxidation states of +2 and +3
  D) form soluble hydroxides
  Show Answer
  The correct answer is A .
• Question 1854: Which of the following statements is correct about the periodic table? Options:
  A) elements in the same period have the same number of valence electrons
  B) the valence electrons of the elements in the same period increase progressively 'across the period
  C) elements in the same group have the same number of electron shell
  D) the non-metallic properties of the elements tend to decrease across each period
  Show Answer
  The correct answer is B .
• Question 1855: Which of the following types of alkanols undergo oxidation to produce alkanoic acids? 1. Primary alkanols 11. Secondary alkanols 111. Tertiary alkanols Options:
  A) 1,11 and 111
  B) l and ll only
  C) ll only
  D) l only
  Show Answer
  The correct answer is D .
• Question 1856: The nucleus of an atom contains Options:
  A) protons only
  B) neurons only
  C) protons and electrons
  D) neutrons and electrons
  E) protons and neutrons
  Show Answer
  The correct answer is E .
• Question 1857:

  

  Choose the correct option from the graph above.

  3Fe_(S) + 4H₂O_(g) ⇌ Fe₃O_4(s) + 4H_2(g). The equilibrium constant, K, of the reaction above is represented as

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 1858: A sample of orange juice is found to have a pH of 3.80. What is he concentration of the hydroxide ion in the juice? Options:
  A) 1.6 x 10^-4
  B) 6.3 x 10^-11
  C) 6.3 x 10^-4
  D) 1.6 x 10^-11
  Show Answer
  The correct answer is B .
• Question 1859:

  

  The figure above shows the electrolysis of molten sodium chloride. Z is the

  Options:
  A) anode where the Cl${}^{-}$ ions are oxidized
  B) cathode where the Cl${}^{-}$ ions are reduced
  C) anode where the Na${}^{+}$ ions are reduced
  D) cathode where the Na${}^{+}$ ions are oxidized
  Show Answer
  The correct answer is A .
• Question 1860:

  If one of the following oxides is heated with hydrogen or carbon using a bunsen burner. it is not reduced to the metal, Which one is it?

  Options:
  A) lead oxide
  B) Magnesium oxide
  C) Copper oxide
  D) Tin oxide
  Show Answer
  The correct answer is B .