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 161: An example of oxidation - reduction enzyme is Options:
  A) amylase
  B) protease
  C) lipase
  D) dehydrogenase
  Show Answer
  The correct answer is D .
• Question 162:

  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 163: Rare gases are suitable because they Options:
  A) are monoatomic
  B) form ions easily
  C) have duplet or octet electronic configuration in the outermost shells in their atoms
  D) are volatile gases
  Show Answer
  The correct answer is C .
• Question 164: The entropy and enthalpy of a system are a measure of Options:
  A) degree of disorderlinesss and heat content respectively
  B) heat content and degree of disorderliness respectively
  C) heat content of a system only
  D) degree of disorderliness only
  Show Answer
  The correct answer is A .
• Question 165:

  In a reaction: SnO + 2C → Sn + 2CO, the mass of coke containing 80% carbon required to reduce 0.302 kg of pure tin oxide is?

  (Sn - 119, O - 16, C - 12).

  Options:
  A) 0.40 kg
  B) 0.20 kg
  C) 0.06 kg
  D) 0.04 kg
  Show Answer
  The correct answer is C .
• Question 166:

  The scientist who stated that matter can be converted into energy is?

  Options:
  A) Boyle
  B) Lavoiser
  C) Avogadro
  D) Einstein
  Show Answer
  The correct answer is D .
• Question 167: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 168: Methanoic acid mixes with water in all proportions and has about the same boiling point as water which of the following methods would you adopt to obtain pure water from a mixture of stand, water and methanoic acid? Options:
  A) fractional distillation
  B) filtration followed by distillation
  C) neutralization with sodium hydroxide followed by distillation
  D) esterification with ethanol followed by distillation
  E) neutralization with sodium hydroxide followed by filtration
  Show Answer
  The correct answer is B .
• Question 169: A suitable reagent for distinguishing between ethanoic acid ethanol is Options:
  A) bromine water
  B) Fehling's solution
  C) sodium hydrogentrioxocarbonate (IV)
  D) ammoniacal silver trioxonitrate (V)
  Show Answer
  The correct answer is C .
• Question 170:

  A few drop of conc HCL are added to about 10cm${}^3$ of a solution of PH 3.4. The PH of the resulting mixture is?

  Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of the pure water
  Show Answer
  The correct answer is A .