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: Which of the following equations show that a reaction is in equilibrium?
  Options:
  A) ΔG < O
  B) ΔG = ΔH – TΔS
  C) ΔG > O
  D) ΔG = O
  Show Answer
  The correct answer is D .
• Question 1132:

  The situation obtained when a perfect gas expands into a vacuum is

  Options:
  A) ΔH is positive and TΔ S is zero
  B) ΔH is positive and T Δ S is negative
  C) ΔH is negative and TΔ S is zero
  D) ΔH is zero and T Δ S is positive
  Show Answer
  The correct answer is D .
• Question 1133: In which of the following is the oxidation state of oxygen different from its value in water? Options:
  A) OH^-
  B) H₃O⁺
  C) O^-
  D) H₂O₂
  E) SO₂
  Show Answer
  The correct answer is D .
• Question 1134:

  What is the maximum number of electrons that can occupy the second energy level (n=2)?

  Options:
  A) 2 electrons
  B) 18 electrons
  C) 8 electrons
  D) 32 electrons
  Show Answer
  The correct answer is C .
• Question 1135: What volume of 0.5 MH₂SO₄ will exactly neutralize 20cm³ of 0.1 MNaOH Solution? Options:
  A) 2.0cm³
  B) 5.0cm³
  C) 6.8cm³
  D) 8.3cm³
  Show Answer
  The correct answer is A .
• Question 1136: When copper powder is heated with concentrated sulphuric acid, the gas produced is? Options:
  A) hydrogen sulphide
  B) sulphur dioxide
  C) sulphur trioxide
  D) hydrogen pentasulphide
  E) sulphur pentoxide
  Show Answer
  The correct answer is B .
• Question 1137: A hydrogen atom which has lost an electron contains Options:
  A) one proton only
  B) one neutron only
  C) one proton and one neutron
  D) one proton, one electron and one neutron
  Show Answer
  The correct answer is A .
• Question 1138: If the electron configuration of a element is p1s² 2s² 2P⁵, how many unpaired electron are there? Options:
  A) 2
  B) 8
  C) 1
  D) 4
  Show Answer
  The correct answer is C .
• Question 1139: Consider the following equation H₂O + 2Fe²⁺ + Cl₂ ↔ 2Fe³⁺ + 2Cl^- + H₂O. The only ion which behaves as an oxidising agent is Options:
  A) Fe²⁺
  B) Cl₂
  C) Fe³⁺
  D) Cl^-
  E) H₂O
  Show Answer
  The correct answer is B .
• Question 1140: A stream of air was successively passed through three tubes X, Y and Z containing a concentrated aqueous solution of KOH, red hot copper powder and fused calcium chloride respectively. What was the composition of the gas emanating from tube Z? Options:
  A) CO₂ ad ithe inert gases
  B) N₂, CO₂ and the inert gases
  C) N₂ and the inert gases
  D) water vapour, N₂ and the inert gases
  Show Answer
  The correct answer is C .