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 131: 2- methylbutan- 2ol is an example of a Options:
  A) dihydric alkanol
  B) tertiary alkanol
  C) secondary alkanol
  D) primary alkanol
  Show Answer
  The correct answer is B .
• Question 132:

  What volume of oxygen will remain after reacting 8cm of hydrogen gas with 20cm of oxygen gas

  Options:
  A) 10cm${}^3$
  B) 12cm${}^3$
  C) 14cm${}^3$
  D) 16cm${}^3$
  Show Answer
  The correct answer is D .
• Question 133:

  How many atoms are present in 6.0g of magnesium? [Mg = 24, N.A = 6.02 x 10 ${}^{23}$mol]

  Options:
  A) 1.20 x 10${}^{22}$
  B) 2.4 x 10${}^{22}$
  C) 1.51 x 10${}^{22}$
  D) 3.02 x 10${}^{22}$
  Show Answer
  The correct answer is C .
• Question 134: In which of the following reactions can the oxidation number of the nitrogen be said to have increased? Options:
  A) 2NO_(g) + O_2(g) → 2NO_2(g)
  B) NO_(g) + Cl_2(g) → NOCl_2(l)
  C) FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
  D) NO_(g) + Br_2(l) → NOBr_2(l)
  Show Answer
  The correct answer is A .
• Question 135: Ammonium chloride can be separated from its mixture with common salt by Options:
  A) Distillation
  B) Evaporation
  C) Decantation
  D) Sublimation
  Show Answer
  The correct answer is D .
• Question 136:

  Which of the following compounds is an example of an electrovalent bond?

  Options:
  A) NaCl (sodium chloride)
  B) CO2 (carbon dioxide)
  C) H2O (water)
  D) CH4 (methane)
  Show Answer
  The correct answer is A .
• Question 137: The function of zinc electrode in a galvanic cells is that it Options:
  A) undergoes reduction
  B) serves as the positive electrode
  C) production electons
  D) uses up electrons
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  The correct answer is C .
• Question 138: The brown fumes given off when trioxonitrate (V) acid is heated consist of ? Options:
  A) NO₂ and O₂
  B) H₂O and NO₂
  C) NO_2' O₂ and H₂O
  D) NO, NO₂ and H₂O
  Show Answer
  The correct answer is C .
• Question 139: In a flame test for calcium, the flame appears Options:
  A) green when viewed through a blue glass
  B) blue when viewed through a blue glass
  C) orange -red when viewed through a blue glass
  D) brick-red when viewed through a blue-glass
  Show Answer
  The correct answer is D .
• Question 140: If 100cm³ of oxygen pass through a porous plug is 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is? [O = 16, H = 1] Options:
  A) 10.0s
  B) 12.5s
  C) 17.7s
  D) 32.0s
  Show Answer
  The correct answer is B .