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 1371:

  What mass of K₂CrO₄ is required to prepare 250cm³ of 0.020 mol dm³ solution?

  [K₂CrO₄ = 194.2g mol^-1]

  Options:
  A) 0.97g
  B) 9.70g
  C) 19.42g
  D) 97.10g
  Show Answer
  The correct answer is A .
• Question 1372:

  A compound contains 40.0% carbon 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, find the molecular formula.

  [H = 1, C = 12, O = 16]

  Options:
  A) CH₂O
  B) C₃H₆O₃
  C) C₆H₁₂O₆
  D) C₆H₁₂O₃
  Show Answer
  The correct answer is C .
• Question 1373:

  2H₂ + O₂2 → H₂+O ΔH = -571kJ

  In the equation above, how much heat will be liberated if 12.0g of hydrogen is burnt in excess oxygen?

  Options:
  A) -1142 kJ
  B) -571 kJ
  C) +1142 kJ
  D) -1713 kJ
  Show Answer
  The correct answer is D .
• Question 1374: Which of the following conduct electricity? Options:
  A) sulfur
  B) graphite
  C) diamond
  D) red phosphorus
  E) yellow phosphorus
  Show Answer
  The correct answer is B .
• Question 1375: Which of the following compounds will burn with a brick-red colour in a non-luminous Bunsen flame? Options:
  A) LiCI
  B) NaCl
  C) CaCl₂
  D) MgCl₂
  Show Answer
  The correct answer is C .
• Question 1376: The shapes of CO${}_2$, H${}_2$O and CH${}_4$ respectively are Options:
  A) bent, linear and tetrahedral
  B) bent, tetrahedral and linear
  C) linear, bent and tetrahedral
  D) tetrahedral, linear and bent
  Show Answer
  The correct answer is C .
• Question 1377: Iron is often galvanized in order to Options:
  A) make it more malleable
  B) remove the impurities in it
  C) protect it against corrosion
  D) render it passive
  Show Answer
  The correct answer is C .
• Question 1378:

  MnO_4(aq) + 8H⁺_(aq) + Y → Mn²⁺_(aq) + 4H₂O_(l)

  Y in the equation above represents

  Options:
  A) 2e^-
  B) 3e^-
  C) 5e^-
  D) 7e^-
  Show Answer
  The correct answer is C .
• Question 1379: The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore Options:
  A) none of these solutions is acidic
  B) the pH of Y is made more acidic by addition of distilled water
  C) Z is the most acidic solution
  D) W is the most acidic solution
  E) X is neutral
  Show Answer
  The correct answer is D .
• Question 1380: The leachate of a certain ash is used in local soap because it contain Options:
  A) sodium chloride and potassium hydroxide
  B) sodium hydroxide
  C) potassium hydroxide
  D) soluble carbonates and hydrogen carbonate
  Show Answer
  The correct answer is B .