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 1881: What amount of mercury would be liberated if the same quantity of electricity that liberates 0.65g of zinc is applied? Options:
  A) 2.01g
  B) 1.00g
  C) 4.02g
  D) 8.04g
  Show Answer
  The correct answer is C .
• Question 1882:

  When chlorine water is exposed to bright sunlight, the following products are formed

  Options:
  A) HCl${}_{(aq)}$ and Cl${}_2$
  B) HOCl${}_{(aq)}$ and Cl${}_2$
  C) HCl${}_{(aq)}$ and O${}_2$
  D) HOCl${}_{(aq)}$ and O${}_2$
  Show Answer
  The correct answer is C .
• Question 1883: The rate of diffusion of a gas Y is twice that of Z If the relative molecular mass of Y is 64 and the two gases diffuse under the same conditions, find the relative molecular mass of Z Options:
  A) 32
  B) 4
  C) 8
  D) 16
  Show Answer
  The correct answer is D .
• Question 1884: How many faraday of electricity is required to produce 0.25 mole of copper? Options:
  A) 1.00F
  B) 0.01F
  C) 0.05F
  D) 0.50F
  Show Answer
  The correct answer is D .
• Question 1885:

  MnO^-4_(aq) + Y + 5Fe²⁺_(aq) → Mn²⁺_(aq) + 5Fe²⁺_(aq) + 4H₂O_(l)
  In the equation above, Y is

  Options:
  A) 5H⁺_(aq)
  B) 4H⁺_(aq)
  C) 10H⁺_(aq)
  D) 8H⁺_(aq)
  Show Answer
  The correct answer is D .
• Question 1886:

  

  In the graph above, the activation energy of the catalyzed reaction is

  Options:
  A) 100KJ
  B) 300KJ
  C) 250KJ
  D) 200KJ
  Show Answer
  The correct answer is A .
• Question 1887:

  What are the possible oxidation numbers of an element if its atomic number is 17?

  Options:
  A) -1 and 7
  B) -1 and 6
  C) -3 and 5
  D) -2 and 6
  Show Answer
  The correct answer is A .
• Question 1888:

  

  The option above shows the PH changes for the titration of a

  Options:
  A) strong acid versus strong base
  B) weak acid versus strong base
  C) strong acid versus weak base
  D) weak acid versus weak base
  Show Answer
  The correct answer is A .
• Question 1889: On recrystallization, 20g of magnesium tetraoxosuphate (IV) forms 41 g of magnesium tetraoxosulphate (IV) crystals, MgSO₄. yH₂O. The value of y is?(Mg = 24, S = 32, O = 16, H = 1) Options:
  A) 1
  B) 3
  C) 5
  D) 7
  Show Answer
  The correct answer is D .
• Question 1890:
  

  Use the section of the periodic table above to answer this question.

  Which letter represents a non-metal that is a solid at room temperature?

  Options:
  A) T
  B) R
  C) J
  D) X
  Show Answer
  The correct answer is A .