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 1:

  The atomic weight of nitrogen is?

  Options:
  A) 10
  B) 12
  C) 14
  D) 16
  Show Answer
  The correct answer is C .
• Question 2: Which of the following statements is true? Options:
  A) an increase in the temperature of a given mass of gas increases the number of gas molecules
  B) an increase in the temperature of the gas does not affect the kinetic energy
  C) an increase in the pressure of the gas is proportional to the increase in volume
  D) a decrease in the pressure of a gas is proportional to the decrease in volume at constant temperature
  E) a decrease in the pressure of the gas decreases the number of gas molecules present
  Show Answer
  The correct answer is D .
• Question 3: Consecutive members of an alkane homologous serires differ by Options:
  A) CH
  B) CH₂
  C) CH₃
  D) C_nH_n
  E) C_nH
  Show Answer
  The correct answer is B .
• Question 4: Diamond cannot be used Options:
  A) In making bicycle chains
  B) As abrasives
  C) In cutting glass and metals
  D) As dies for drawing wires
  Show Answer
  The correct answer is A .
• Question 5: It is not desirable to use lead tetraethyl as an anti-knock agent because? Options:
  A) it is expensive
  B) of pollution effects from the exhaust fumes
  C) it lowers the octane rating of petrol
  D) it is explosive
  Show Answer
  The correct answer is B .
• Question 6: The solubility product of Cu(IO₃)₂ is 1.08 * 10^-7. Assuming that neither ions react appreciable with water to form H⁺ and OH^-, what is the solubility of this salt? Options:
  A) 2.7 * 10^-8 mol dm^-3
  B) 9.0 * 10^-8 mol dm^-3
  C) 3.0 * 10^-3 mol dm^-3
  D) 9.0 * 10^-3 mol dm^-3
  Show Answer
  The correct answer is D .
• Question 7: When excess ethanol is heated to 145^oC in the presence of concentrated H₂SO₄, the product is Options:
  A) ethyne
  B) diethyl sulphate
  C) diethyl ether
  D) acetone
  Show Answer
  The correct answer is C .
• Question 8:

  When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called

  Options:
  A) electrovalent bond
  B) co-ordinate bond
  C) ionic bond
  D) covalent bond
  Show Answer
  The correct answer is B .
• Question 9: In the chemical reaction A + B $\to$ C + D, more of D is formed? Options:
  A) if the concentrated of A is reduced
  B) if the concentrated of B is reduced
  C) if the concentrated of C is reduced
  D) if the concentration of C is increased
  E) if D is continuously removed from the reaction mixture
  Show Answer
  The correct answer is E .
• Question 10: The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as; Options:
  A) saponification
  B) dehydration
  C) esterification
  D) hydrolysis
  E) hydration
  Show Answer
  The correct answer is C .