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 461: In the process of silver-plating a metal M, the metal M is the? Options:
  A) anode and a driect current is used
  B) cathode and an alternating current is used
  C) anode and an alternating current is used
  D) cathode and a direct current is used
  Show Answer
  The correct answer is B .
• Question 462: What happens when zinc rod is immersed in copper (II) tetraoxosulphate (VI) solution/ Options:
  A) The blue colour of the solution disappears
  B) Electrons flow from copper to zinc
  C) The zinc rod remain undissolved
  D) The copper generate more copper ions
  Show Answer
  The correct answer is A .
• Question 463:

  Pure sulphuric acid is a liquid of 1:84 density. What volume of it would be required to prepare 250 cm³ of 2.0 M solution?

  (H = 1, S = 32, O = 16)

  Options:
  A) 2.00
  B) 2.66
  C) 3.00
  D) 3.66
  E) 4.00
  Show Answer
  The correct answer is B .
• Question 464: X_(g) + 3Y_(g) ---- 2z_(g) H = +ve. if the reaction above takes place at room temperature, the G will be Options:
  A) negative
  B) zero
  C) positive
  D) indeterminate
  Show Answer
  The correct answer is D .
• Question 465: If the relative molecular mass of an element is not a whole number, it can be deduced that the element is Options:
  A) naturally radioactive
  B) abundant in nature
  C) a transition metal
  D) an isotopic mixture
  Show Answer
  The correct answer is D .
• Question 466: The weakest attractive force that can be observed between two molecules is Options:
  A) ionic
  B) covalent
  C) co-ordinate covalent
  D) vander Waals
  Show Answer
  The correct answer is D .
• Question 467:

  SO${}_3$ is not directly dissolved in water in the industrial preparation of H${}_2$SO${}_4$ by the contact process because

  Options:
  A) SO${}_3$ is an acidic gas
  B) Acid is usually added to water and not water to acid
  C) The reaction between SO${}_3$ and water is violently exothermic
  D) SO${}_3$ does not dissolve readily in water
  Show Answer
  The correct answer is C .
• Question 468:

  What is the atomic number of aluminium?

  Options:
  A) 13
  B) 26
  C) 14
  D) 12
  Show Answer
  The correct answer is A .
• Question 469: When ΔH is negative, a reaction is said to be Options:
  A) ionic
  B) reversible
  C) exothermic
  D) endothermic
  Show Answer
  The correct answer is C .
• Question 470:

  

  Choose the correct option from the graph above.

  3Fe_(S) + 4H₂O_(g) ⇌ Fe₃O_4(s) + 4H_2(g). The equilibrium constant, K, of the reaction above is represented as

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