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 1491:

  The ratio of the initial to the final pressure of a given mass of gas is 1:1.5. Calculate the final volume of the gas if the initial volume was 300cm${}^3$ at the same temperature.

  Options:
  A) 120cm${}^3$
  B) 200cm${}^3$
  C) 450cm${}^3$
  D) 750cm${}^3$
  Show Answer
  The correct answer is B .
• Question 1492:

  What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

  [H = 1, O = 16]

  Options:
  A) 36.0g
  B) 8.0g
  C) 72.0g
  D) 16.0g
  Show Answer
  The correct answer is C .
• Question 1493: 0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64] Options:
  A) 64.0g
  B) 32.0g
  C) 16.0g
  D) 6.4 g
  E) 3.2g
  Show Answer
  The correct answer is E .
• Question 1494: A pure solid usually melts? Options:
  A) over a wide range of temperature
  B) over a narrow range of temperature
  C) at a lower temperature than the impure one
  D) at the same temperature as the impure one
  Show Answer
  The correct answer is B .
• Question 1495: An anhydride is an oxide of non-mental? Options:
  A) which will not dissolve in water
  B) whose solution in water has a pH greater than 7
  C) whose solution in water has a pH less than 7
  D) whose solution in water has a pH of 7
  Show Answer
  The correct answer is C .
• Question 1496: A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is Options:
  A) 1,800 kg
  B) 900 kg
  C) 600 kg
  D) 2, 400 kg
  E) 1, 200 kg
  Show Answer
  The correct answer is D .
• Question 1497: An example of a hygroscopic substance is Options:
  A) CuO _(S).
  B) MgCL_2(S).
  C) CaCL_2(S).
  D) NaOH_(S).
  Show Answer
  The correct answer is A .
• Question 1498:

  Two equal bulbs, one containing ammonia and the other nitrogen are opened mouth-to-mouth to each other at room temperature. The entropy in the mixture of gases is likely to

  Options:
  A) remain unchanged
  B) increase
  C) decrease
  D) change
  Show Answer
  The correct answer is B .
• Question 1499: Unsaturated organic compounds are identified by decolourization of Options:
  A) silver bromine and potassium tetraoxomanganate (VII) solutions
  B) bromine water and acidified potassium tetraoxomanganate (VII) solution
  C) silver bromide solution and bromine water
  D) bromine water and alkaline potassium tetraoxomanganate (VII) solution
  Show Answer
  The correct answer is B .
• Question 1500: Which of the following is used in fire extinguishers? Options:
  A) Carbon (ll) oxide
  B) Carbon (lV) oxide
  C) Sulphur (lV) oxide
  D) Ammonia
  Show Answer
  The correct answer is B .