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 1871: How many moles of HCl will be required to react with potassium heptaoxodichromate (VI) to produce 3 moles of chlorine? Options:
  A) 14
  B) 12
  C) 11
  D) 10
  Show Answer
  The correct answer is A .
• Question 1872:

  A radioactive nucleus has a half-life of 20 years, starting with 100,000 particles, how many particles will be left exactly at the end of 40 years

  Options:
  A) 75,000 particles
  B) 35,000 particles
  C) 25,000 particles
  D) 50,000 particles
  Show Answer
  The correct answer is C .
• Question 1873:

  With conc H₂SO₄ as catalyst

  CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O

  Options:
  A) esterification
  B) Condensation
  C) saponification
  D) neutralization
  Show Answer
  The correct answer is A .
• Question 1874:

  The only metal that is anti-bacterial is?

  Options:
  A) Iron
  B) Sodium
  C) Alluminium
  D) Copper
  Show Answer
  The correct answer is D .
• Question 1875:

  C₁₂H₂₂O_11(s) + H₂SO_4(aq) 12C_(s) + 11H₂O_(l) + H₂SO_4(aq)

  In the reaction above, tetraoxosulphate (VI) acid function as

  Options:
  A) A dehydrate agent
  B) An oxidizing agent
  C) A reducing agent
  D) A catalyst
  Show Answer
  The correct answer is A .
• Question 1876: For iodine crystals to sublime on heating, the molecules must acquire energy that is? Options:
  A) less than the forces odf attraction in the solid
  B) equal to the forces of attraction in th solid
  C) necessary to melt the solid
  D) greater than the forces of attraction in both the solid and the liquid phases
  Show Answer
  The correct answer is D .
• Question 1877: When ΔH is negative, a reaction is said to be Options:
  A) ionic
  B) reversible
  C) exothermic
  D) endothermic
  Show Answer
  The correct answer is C .
• Question 1878:

  The fourteen elements (atomic number 90-103) after actinium are called?

  Options:
  A) Actinoids
  B) Nucleotides
  C) Pre-actinum elements
  D) Atomic elements
  Show Answer
  The correct answer is A .
• Question 1879:

  In the preparation of salts, the method employed will depend on the?

  Options:
  A) composition
  B) dissociating ability
  C) stability to heat
  D) precipitating ability
  Show Answer
  The correct answer is C .
• Question 1880: SO₃ is NOT directly dissolved in water in the preparation of H₂SO₄ by the contact process because? Options:
  A) the reaction between SO₃ and water is violently exothermic
  B) acid is usually added to water and never water to acid
  C) SO₃ does not dissolve in water readily
  D) SO₃ is an acid gas
  Show Answer
  The correct answer is A .