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 771: In the electrolytic extraction of cacium from calcium chloride, the cathode is Options:
  A) zinc
  B) graphite
  C) platinum
  D) iron
  Show Answer
  The correct answer is D .
• Question 772:

  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 773:

  The heat of reaction can be determined experimentally using a device called a

  Options:
  A) Calorimeter
  B) Barometer
  C) Spectrometer
  D) Thermometer
  Show Answer
  The correct answer is A .
• Question 774:

  

  Use the table above to answer this question .The least reactive element is

  Options:
  A) W
  B) X
  C) Y
  D) Z
  Show Answer
  The correct answer is D .
• Question 775: The atomic number of caesium is 55 and its atomic mass is 133. The nucleus of caesium atom therefore contains Options:
  A) 78 protons and 55 elections
  B) 55 protons and 78 neutrons
  C) 55 neutrons 78 electrons
  D) 78 protons and 55 neutrons
  Show Answer
  The correct answer is B .
• Question 776: In the laboratory preparation of trioxonitrate (V) acid the nitrogen(iv) oxide formed as a by-product is removed by Options:
  A) further heating
  B) adding concentrated H₂SO₄
  C) cooling the acid solution with cold water
  D) bubbling air through the acid solution
  Show Answer
  The correct answer is D .
• Question 777:

  Why is water often referred to as the "universal solvent"?

  Options:
  A) Water is the most abundant substance on Earth
  B) Water is essential for all living organisms.
  C) Water is involved in many chemical reactions
  D) Water can dissolve a wide variety of substances due to its polar nature
  Show Answer
  The correct answer is D .
• Question 778:

  2SO_2(g) + O_2(g) ↔ 2SO_3(g)

  ΔH = -189 kJ mol^-1

  The equilibrium constant for the reaction above is increased by

  Options:
  A) Increasing the temperature of the system
  B) Increase the pressure of the system
  C) The addition of a catalyst to the system
  D) Increasing the surface area of the vessel
  Show Answer
  The correct answer is B .
• Question 779: A mixture of sugar and sulphur can be separated by Options:
  A) dissolution in water, evapouration and filtration
  B) filtration, evaporation and dissolution in water
  C) dissolution in water, filtration and evaporation
  D) evaporation, dissolution in water and filtration
  Show Answer
  The correct answer is C .
• Question 780: The principal constituent of natural gas is Options:
  A) methane
  B) ethane
  C) propane
  D) Butane
  Show Answer
  The correct answer is A .