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 1091:

  An organic compound contains 69% carbon, 15.3% hydrogen and 30.7% oxygen. Calculate the the empirical formula [C=12, H = 1, O = 16]

  Options:
  A) C${}_4$H${}_{1}2$O
  B) C${}_3$H${}_9$O
  C) C${}_4$H${}_9$O
  D) C${}_3$H${}_8$O
  Show Answer
  The correct answer is D .
• Question 1092: The relative atomic mass of a naturally occurring lithium consisting of 90%$\frac{7}{3}$Li and 10%$\frac{6}{3}$Li is Options:
  A) 6.2
  B) 6.8
  C) 7.1
  D) 6.9
  Show Answer
  The correct answer is D .
• Question 1093:

  The heat of reaction can be determined experimentally using a device called a

  Options:
  A) Calorimeter
  B) Barometer
  C) Spectrometer
  D) Thermometer
  Show Answer
  The correct answer is A .
• Question 1094: 2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of? Options:
  A) constant composition
  B) conservation of mass
  C) reciprocal proportions
  D) multiple proportions
  Show Answer
  The correct answer is D .
• Question 1095: In the laboratory preparation of chlorine from concentrated hydrochloric acid in the presence of potassuim tetraoxomanganate(VII) the produced is dried by passing it through Options:
  A) Concentrated tetraoxosulphate (VI) acid
  B) Anhydrous calcium chloride
  C) Calcium oxide
  D) Sodium hydroxide
  Show Answer
  The correct answer is A .
• Question 1096: Smoke consist of? Options:
  A) solid particles dispersed in liquid
  B) solid or liquid particles dispersed in gas
  C) gas or liquid particles dispersed inliquid
  D) liquid particles dispersed inliquid
  Show Answer
  The correct answer is B .
• Question 1097:

  

  In the diagram above, the gas produced is

  Options:
  A) NO
  B) NO₂
  C) N₂O
  D) N₂O₄
  Show Answer
  The correct answer is A .
• Question 1098: Which of the following is an acidic salt? Options:
  A) NaHSO₄
  B) Na₂SO₄
  C) CH₃CO₂Na
  D) Na₂S
  Show Answer
  The correct answer is A .
• Question 1099:

  

  In the diagram above, which of the curves represents the evolution of oxygen with time in the equation 2KClO_3(s) → 2KCl_(s) + 3O_2(g)?

  Options:
  A) X
  B) Y
  C) Z
  D) R
  Show Answer
  The correct answer is C .
• Question 1100: The number of hydroxonium ions produced by one molecule of an acid in aqueous solution is its Options:
  A) basicity
  B) acid strength
  C) pH
  D) concentration
  Show Answer
  The correct answer is B .