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 661: The process that occurs when two equivalent forms of a compound are in equilibrium is Options:
  A) Isotopy
  B) Resonance
  C) Isomerism
  D) Reforming
  Show Answer
  The correct answer is B .
• Question 662: A reaction takes places spontaneously if?
  Options:
  A) ∆G = O
  B) ∆S < O and ∆H > O
  C) ∆H < T ∆S
  D) ∆G > O
  Show Answer
  The correct answer is C .
• Question 663: Bleaching powder, CaOCI₂, H₂O, deteriorates on exposure to air because Options:
  A) it loses its water of crystallization
  B) atmospheric nitrogen displaces chlorine from it
  C) carbon (IV) oxide of the atmosphere displaceschlorine from it
  D) bleaching agents should be stored in solution
  Show Answer
  The correct answer is C .
• Question 664: The reaction of an alkanol with an alkanoic acid in the presence of concentrated H₂SO₄ will produce an? Options:
  A) alkanal
  B) alkanoate
  C) alkanone
  D) alkyne
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  The correct answer is B .
• Question 665:

  The two ions responsible for hardness in water are

  Options:
  A) Ca${}^{2+}$ and / or Mg${}^{2+}$
  B) K${}^{+}$ and / or Mg${}^{2+}$
  C) Ca${}^{2+}$ and / or Li${}^{+}$
  D) Ca${}^{2+}$ and / or Na${}^{+}$
  Show Answer
  The correct answer is A .
• Question 666: Bronze is an alloy of Options:
  A) copper, zinc and nickel
  B) aluminium and copper
  C) copper and zinc
  D) tin and zinc
  E) tin and copper
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  The correct answer is E .
• Question 667:

  Consider the following exothermic reaction

  2SO_2(g) + O_2(g) ↔ 2SO_3(g)

  If the temperature of the reaction is reduced from 800°C to 500°C, an no other change takes place, then

  Options:
  A) the reaction rate increases
  B) concentration of SO₃ decreases
  C) concentration of SO₃ increases
  D) SO₂ gas becomes unreactive
  E) O₃ gas becomes unreactive
  Show Answer
  The correct answer is C .
• Question 668: Chlorine consisting of two isotopes of mass number 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotopes of mass number 37 Options:
  A) 20
  B) 25
  C) 60
  D) 75
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  The correct answer is B .
• Question 669:

  

  The I.U.P.A.C name for the compound

  Options:
  A) 2-chloro-isopentane
  B) 3-chloro-isopentane
  C) 2-chloro-2-methylbutane
  D) 1-chloro-2,2- dimethylpropane
  E) 2-chloro-2-ethylpropane
  Show Answer
  The correct answer is C .
• Question 670:

  

  The elections or two atoms Y and Z are arranged in shes as shown above. The bond formed between the atoms of Y and Z is

  Options:
  A) ionic
  B) convalent
  C) dative
  D) metallic
  Show Answer
  The correct answer is B .