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 1401: An iron ore is known to contain 70.0% Fe₂O₃. The obtain from 80kg of the ore is?(Fe = 56, O = 16) Options:
  A) 35.0 kg
  B) 39.2 kg
  C) 70.0 kg
  D) 78.4 kg
  Show Answer
  The correct answer is B .
• Question 1402: The three-dimensional shape of methane is Options:
  A) hexagonal
  B) trigonal
  C) linear
  D) tetrahedral
  E) cubical
  Show Answer
  The correct answer is D .
• Question 1403:

  When anhydrous cobalt chloride paper is exposed to water, what color change is observed?

  Options:
  A) From pink to blue
  B) From white to blue
  C) From blue to white
  D) From blue to pink
  Show Answer
  The correct answer is D .
• Question 1404: The formula for ethyl butanoate is Options:
  A) C₃H₇COOC₂H₅
  B) C₂H₅COOC₃H₇
  C) C₄H₉COOC₂H₅
  D) C₂H₅COOC₄H₉
  Show Answer
  The correct answer is A .
• Question 1405: Sulphur exists in six forms in the solid state. This property is known as? Options:
  A) isomerism
  B) allotropy
  C) isotopy
  D) isomorphism
  Show Answer
  The correct answer is B .
• Question 1406:

  Which of the following best represent solid gas mixture?

  Options:
  A) milk
  B) kerosene
  C) soil
  D) smoke
  Show Answer
  The correct answer is D .
• Question 1407: In which of the following reactions does hydrogen peroxide act as a reducing agent? Options:
  A) H₂S + H₂O₂ $\to$ S + 2H₂O
  B) PbSO₃ + H₂O₂ $\to$ PbSO₄ + H₂O
  C) 2I+ 2H⁺ + H₂O₂ $\to$ I₂ + 2H₂O
  D) PbO₂ + 2HNO₃ + H₂O₂ $\to$ Pb(NO₃)₂ + 2H₂O + O₂
  E) SO₂ + H₂O₂ $\to$ H₂SO₄
  Show Answer
  The correct answer is D .
• Question 1408: On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced? Options:
  A) SO₂ (g) + FeS (s)
  B) SO₃ (g) +FeS(s)
  C) SO₂ (g) + SO₃(g)
  D) SO₂ (g) + H₂S (g)
  E) SO₃(g) + H₂S(g)
  Show Answer
  The correct answer is C .
• Question 1409:

  Which noble gas is radioactive and is produced as a decay product of uranium and thorium?

  Options:
  A) Argon
  B) Krypton
  C) Radon
  D) Neon
  Show Answer
  The correct answer is C .
• Question 1410:

  A gaseous metallic chloride MCl_x consists of 20.22% of M by mass. The formula of the chloride is

  [M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl₂
  C) MCl₃
  D) M₂Cl₆
  Show Answer
  The correct answer is C .