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 2041: If hydrogen sulphide gas is passed into a solution of a pure iron chloride, a yellow deposit appears. If the deposit is filtered, a pale green solution is left behind. The pale green solution is Options:
  A) dilute sulphuric acid
  B) dilute hydrochloric acid
  C) unreacted hydrogen sulphide in water
  D) iron (III) chloride
  E) Iron (II) chloride
  Show Answer
  The correct answer is E .
• Question 2042:

  The periodic classification is an arrangement of the elements

  Options:
  A) atomic weights
  B) isotopic weights
  C) molecular weights
  D) atomic numbers
  Show Answer
  The correct answer is D .
• Question 2043:

  

  Use the following option above to answer this question. Which of the following compounds in solution will turn red litmus paper blue?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 2044:

  Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 

  Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is B .
• Question 2045: Which of the following are the products of the reaction between CH₃COOH and CI₂ in sunlight? Options:
  A) CICH₂COOH + HCI
  B) CH₃COCI + HOCI
  C) CH₃COOCI + HCI
  D) CH₃COCI + HO₂
  Show Answer
  The correct answer is A .
• Question 2046:

  In the reactions

  (I) H₂ (g) + 1/2O₂(g) → H₂O(l); ∆H = -286 KJ

  (II) C(s) + O₂g) → CO₂ (g); ∆H = -406 KJ the equations imply that

  Options:
  A) more heat is absorbed in (l)
  B) more heat is absorbed in (ll)
  C) less heat is evolved in (l)
  D) reaction (ll) proceeds faster than (l)
  E) reaction (l) proceeds faster than (ll)
  Show Answer
  The correct answer is C .
• Question 2047: A compound that gives a brick-red colour to a non-luminous flame is likely to contain Options:
  A) copper ions
  B) sodium ions
  C) calcium ions
  D) aluminium ions
  Show Answer
  The correct answer is C .
• Question 2048: The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ Options:
  A) - 2792
  B) + 2792
  C) - 64
  D) + 64
  Show Answer
  The correct answer is D .
• Question 2049:

  A cell shorthand notation can be written as A / A${}^{+}$ // B${}^{2+}$ /B. The double slash in the notation represents the 

  Options:
  A) electrolyte
  B) electrodes
  C) salt bridge
  D) solid - liquid interface
  Show Answer
  The correct answer is C .
• Question 2050:

  Which of the following is a redox reaction?

  Options:
  A) KCI_(aq) + H₂SO_4(aq) → KHSO_4(aq) + HCI_(aq)
  B) 2FeBr_2(aq) + Br_4(aq) → 2FeBr_3(aq)
  C) 3AgNO_(aq) + FeCl_3(aq) → 3AgCl_(aq) + Fe(NO₃)_3(aq)
  D) H₂CO_3(aq) → H₂O_(I)2- + CO_2(g)
  Show Answer
  The correct answer is B .