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 1541:

  Which of the following metals is commonly alloyed with copper to make brass?

  Options:
  A) Iron
  B) Nickel
  C) Aluminum
  D) Zinc
  Show Answer
  The correct answer is D .
• Question 1542: A carcinogenic substance is Options:
  A) asbestos dust
  B) sawdust
  C) nitrogen (II) oxide
  D) carbon (II) oxide
  Show Answer
  The correct answer is A .
• Question 1543:

  2SO${}_2$ ${}_{(g)}$+ O${}_2$ ${}_{(g)}$ ↔ 2SO${}_3$${}_{(g)}$ ΔH = -395.7kJmol${}^{-1}$

  In the equation, an increase in temperature will shift the equilibrium position to the

  Options:
  A) left and equilibrium constant decreases
  B) left and equilibrium constant increases
  C) right and equilibrium constant increases
  D) right and equilibrium constant decreases
  Show Answer
  The correct answer is A .
• Question 1544:

  2Cl_2(g) + 2H₂O_(g) 4HCl_(g) + O_2(g)

  ∆H° = +115KJ mol^-1. In the above equilibrium reaction, a decrease in temperature will?

  Options:
  A) favour the reverse reaction
  B) favour the forward reaction
  C) have no effect on the equilibrium state
  D) double the rate of the reverse raection
  Show Answer
  The correct answer is A .
• Question 1545:

  The reactions involving simultaneous oxidation and reduction?

  Options:
  A) Automatic reactions
  B) Alternate reactions
  C) Reduction agency
  D) Redox reactions
  Show Answer
  The correct answer is D .
• Question 1546:

  2H₂O _(l) + 2F_2(g) → 4HF_(aq) + O_2(g).

  In the reaction above, the substance that is being reduced is

  Options:
  A) O_2(g)
  B) H₂O_(l)
  C) F_2(g)
  D) HF_(aq)
  Show Answer
  The correct answer is C .
• Question 1547: Synthesis gas is a mixture of Options:
  A) CH₄ and H₂O
  B) CH₄ and H₂
  C) CO₂ and H₂
  D) CO and H₂
  Show Answer
  The correct answer is D .
• Question 1548:

  

  The diagram above best illustrates the effect of decrease in

  Options:
  A) concentration
  B) temperature
  C) surface area
  D) pressure
  Show Answer
  The correct answer is A .
• Question 1549: Which of the following compounds is the best possible anti-knock agent for petrol? Options:
  A) (CH₃)₂CH - CH(CH₃)CH₂CH₃
  B) CH₃CH₂(CH₃)CHCH₂CH₂CH₃
  C) CH₃CH₂(CH₃)CHCH₂CH₂CH₃
  D) (CH₃)₃C - CH₂CH₂CH₃
  Show Answer
  The correct answer is A .
• Question 1550: A cold aqueous solution of sodium chloride is electrolyzed using a graphite anode and an iron cathode. In the course of the electrolysis the electrolyte is continuously stirred. The liquid left after electrolysis will therefore consist of? Options:
  A) sodium hydroxide solution
  B) chlorine water
  C) pure water
  D) sodium hypochlorite solution
  E) hydrochloric acid solution
  Show Answer
  The correct answer is B .