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 1131: When excess chlorine is mixed with ethene at room temperature, the product is Options:
  A) 1,2 - dichloroethane
  B) 1,2 - dichloroethene
  C) 1,1 - dichloroethane
  D) 1, 1 - dichloroethene
  Show Answer
  The correct answer is A .
• Question 1132: The products of the combustion of candle wax are Options:
  A) hydrogen and water
  B) oxygen and water
  C) carbon (IV) oxide and water
  D) carbon (II) oxide and water
  Show Answer
  The correct answer is C .
• Question 1133: The gas that will form a white precipitate with acidified silver trioxonitrate (v) is Options:
  A) NH₃
  B) SO₂
  C) CO₂
  D) HCL
  Show Answer
  The correct answer is D .
• Question 1134: A substance S is isomorphous with another substance R. When a tiny crystals of S is added into a supersaturated solution of R? Options:
  A) S dissolves in the solution
  B) crystals of R are precipitated
  C) there is no observable change
  D) R and S react to generate heat
  Show Answer
  The correct answer is B .
• Question 1135: An acid is said to be weak if? Options:
  A) its ions are so completely dissociated that they easily drift apart
  B) the acid is not corrosive
  C) the acid has low specific gravity
  D) its ions move very slowly when in solution
  E) its ions are incompletely dissociated
  Show Answer
  The correct answer is E .
• Question 1136: 2SO_2(g) + O_2(g) 2SO₃. In the reaction above, the standard heats of formation of SO_2(g) and SO_3(g) are -297 KJ mol^-1 respectively. The heat change of the reaction is? Options:
  A) -99 kJ mol^-
  B) -198 kJ mol^-
  C) +198 kJ mol^-
  D) +683kJ mol^-
  Show Answer
  The correct answer is B .
• Question 1137:

  What number of moles of Cu ²⁺ will be deposited by 360 coulombs of electricity?

  [f = 96500 C mol ^-1]

  Options:
  A) 5.36 x 10 ^-4 mole
  B) 1. 87 x 10 10 ^-3 mole
  C) 9. 35 x 10 ^-4 mole
  D) 3. 73 x 10 ^-3
  Show Answer
  The correct answer is B .
• Question 1138: Which of the following metals is purified commercially by electrolysis? Options:
  A) Zn
  B) Fe
  C) Sn
  D) Cu
  Show Answer
  The correct answer is D .
• Question 1139: Arrange HCI, CH₃COOH, C₆H₅CH₃ in order of increasing conductivity. Options:
  A) HCI, CH₃COOH, C₆H₅CH₃
  B) C₆H₅CH₃, HCI, CH₃COOH
  C) C₆H₅CH₃, CH₃COOH, HCI
  D) CH₃COOH, C₆H₅CH₃, HCI
  Show Answer
  The correct answer is C .
• Question 1140:

  How many moles of copper would be deposited by passing 3F of electricity through a solution of copper (II) tetraoxosulpohate (IV)?

  (F = 96 500 C mol^-)

  Options:
  A) 0.5
  B) 1.0
  C) 1.5
  D) 3.0
  Show Answer
  The correct answer is C .