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 1921:

  When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is

  Options:
  A) propylmethanoate
  B) ethylpropanoate
  C) methyl ethanoate
  D) methyl propanoate
  Show Answer
  The correct answer is B .
• Question 1922: To what temperature must a gas 273 K be heated in order to double both its volume and pressure? Options:
  A) 298 K
  B) 546 K
  C) 819 K
  D) 1092 K
  Show Answer
  The correct answer is D .
• Question 1923: Which of the following will produce a solution with pH less than 7 at equivalent point? Options:
  A) HNO ₃ +NaOH
  B) H ₂SO ₄ + KOH
  C) HC +Mg (OH) ₂
  D) HNO ₃ + KOH
  Show Answer
  The correct answer is C .
• Question 1924: There are basic particles from which matter called be made except Options:
  A) Salt
  B) Atom
  C) Ion
  D) Molecule
  Show Answer
  The correct answer is A .
• Question 1925:

  Consider the equation below:

  Cr${}_2$O${}_7^{2-}$ + 6Fe${}^{2+}$ + 14H${}^{+}$ $\to$ 2Cr${}^{3+}$ + 6Fe${}^{3+}$ + 7H${}_2$O.

  The oxidation number of chromium changes from

  Options:
  A) +5 to +3
  B) +6 to +3
  C) -2 to +3
  D) +7 to +3
  Show Answer
  The correct answer is B .
• Question 1926: The metal whose ore can be concentrated by passing it through a magnetic separator is Options:
  A) Zn
  B) Sn
  C) Cn
  D) Ca
  Show Answer
  The correct answer is B .
• Question 1927:

  

  The IUPAC nomenclature for the compound above is

  Options:
  A) 4-methylpent-1-ene
  B) 3-methylpent-2-ene
  C) 2-methylpent-1ene
  D) 2-methylpent-4-ene
  Show Answer
  The correct answer is A .
• Question 1928:

  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 1929: Which of the following is NOT an alkali? Options:
  A) NH₃
  B) Mg(OH)₂
  C) Ca(OH)₂
  D) NaOH
  Show Answer
  The correct answer is A .
• Question 1930: 50 cm³ of carbon (II) oxide was exploded with 150 cm³ of air containing 20% oxygen by volume. Which of the reactants was in excess? Options:
  A) Carbon (II) oxide
  B) Carbon (IV) oxide
  C) Oxygen
  D) Nitrogen
  Show Answer
  The correct answer is C .