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 711: Which of the following pair of gases will NOT react further with oxygen at a temperature between 30^oC AND 400^oC Options:
  A) SO₂ and NH₃
  B) CO₂ and H₂
  C) NO₂ and SO₃
  D) SO₃ and NO
  E) CO and H₂
  Show Answer
  The correct answer is C .
• Question 712: 60cm³ of hydrogen are sparked with 20cm³ of oxygen at 100°C and 1 atmosphere. The total volume of the residual gases is? Options:
  A) 60 cm³
  B) 10 cm³
  C) 40 cm³
  D) 30 cm³
  E) 70 cm³
  Show Answer
  The correct answer is A .
• Question 713: The metal that liberates hydrogen from cold water in bubbles only is Options:
  A) Na
  B) K
  C) Ca
  D) Al
  Show Answer
  The correct answer is C .
• Question 714:

  NH₄Cl_(s) ↔ NH_3(g) + HCL_(g)

  The reaction above can only attain equilibrium if

  Options:
  A) a gaseous reactant is added
  B) one of the products is removed
  C) it is in a closed system
  D) it is an open system
  Show Answer
  The correct answer is C .
• Question 715: The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol^-1) Options:
  A) 54.0g
  B) 27.0g
  C) 13.5g
  D) 108.0g
  Show Answer
  The correct answer is A .
• Question 716:

  

  The diagram above (Fig.3) shows the energy profile for the reaction A + B + = C + D From this diagram, it is clear that the reaction is

  Options:
  A) spontaneous
  B) isothermal
  C) adiabatic
  D) exothermic
  E) endothermic
  Show Answer
  The correct answer is D .
• Question 717: An elements X with relative atomic mass 16.2 contains two isotopes ¹⁶₈X with relative abundance of 90% and ^m₈X with relative abundance of 10%. The value of m is Options:
  A) 16
  B) 18
  C) 12
  D) 14
  Show Answer
  The correct answer is B .
• Question 718:

  

  It can be deduced from the vapour pressure curves above that

  Options:
  A) liqiud 1 has the highest boiling point
  B) liquid ll has the highest boiling point
  C) liquid lll has the highest boiling point
  D) liquid lll has the lowest boiling point
  Show Answer
  The correct answer is C .
• Question 719:

  56.00cm³ of a gas at S.T.P. weighed 0.11g. What is the vapour density of the gas?
  [Molar volume of a gas at S.T.P = 22.4dm³]

  Options:
  A) 11.00
  B) 22.00
  C) 33.00
  D) 44.00
  Show Answer
  The correct answer is B .
• Question 720: The compounds CH₃CH₂CHO and CH₃COCH₃ can be distinguished from each other using Options:
  A) Dilute ammonia
  B) Benedict's solution
  C) Tollen's reagent
  D) Sodium hydroxide solution
  Show Answer
  The correct answer is C .