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 1351: Vulcanization involve the removal of Options:
  A) monometer
  B) the single bond
  C) the double bond
  D) a polymer
  Show Answer
  The correct answer is C .
• Question 1352: Which of the following substances is the most abundant in the universe? Options:
  A) Carbon
  B) Air
  C) Water
  D) Oxygen
  E) Hydrogen
  Show Answer
  The correct answer is E .
• Question 1353: Which of the following decreases when a given mass of gas is compressed to half its initial volume? Options:
  A) Average intermolecular distance
  B) Frequency of collisions
  C) Number of molecules present
  D) Atomic radius of each particle
  Show Answer
  The correct answer is A .
• Question 1354:

  How many grams of hydrogen gas will be liberated when 6g of magnesium ribbon dissolves in 500cm³ of 6M HCl?

  (Mg=24, H=1, Cl=35.5)

  Options:
  A) 1.2 g
  B) 0.7 g
  C) 0.5 g
  D) 0.3 g
  E) 0.12 g
  Show Answer
  The correct answer is C .
• Question 1355: N₂O_4(g) ↔ 2NO_2(g). Increase in total pressure of the equilibrium reaction above will Options:
  A) produce more of NO_2(g) in the mixture
  B) convert all of N₂O_4(g) to NO_2(g)
  C) have no effect on the concentrations of NO_2(g)and N₂O_4(g)
  D) produce more of N₂O_4(g) in the mixture
  Show Answer
  The correct answer is D .
• Question 1356:

  2SO_2(g) + O_2(g) $⟺$2SO_3(g)

  $△H=-395.7kJmo{l}^{-1}$

  In the reaction above, the concentration of 2SO_3(g) can be in creased by

  Options:
  A) decreasing the pressure
  B) decreasing the temperature
  C) the addition of catalyst
  D) increasing the temperature
  Show Answer
  The correct answer is B .
• Question 1357: In what respect will two dry samples of nitrogen gas differ from each other if sample 1 is prepared by completely removing CO₂ and O₂ from air, and sample 2 is prepared by passing purified nitrogen(i)oxide over heated copper? sample 1 is Options:
  A) purer than sample 2
  B) slightly denser than sample 2
  C) in all respects the same as sample 2
  D) colourless but sample 2 has a light brown colour
  E) slightly less reactive than sample 2
  Show Answer
  The correct answer is B .
• Question 1358:

  2X_(aq) + MnO_2(s) + 4H⁺_(aq) → X_2(g) + Mn²⁺_(aq) + 2H₂O.

  The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?

  Options:
  A) a poisionous gas
  B) an oxidizing agent
  C) electronegative in nature
  D) highly reactive
  Show Answer
  The correct answer is D .
• Question 1359: A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by Options:
  A) boiling the water
  B) adding excess calcium hydroxide
  C) adding a calculated amount of calcium hydroxide
  D) adding sodium carbonate
  E) adding magnesium hydroxide
  Show Answer
  The correct answer is D .
• Question 1360: If the cost of electricity required to deposit 1 g of magnesium is ₦5.00, how much would it cost to deposit 10g of aluminium? Options:
  A) ₦10.00
  B) ₦27.00
  C) ₦44.44
  D) ₦66.67
  E) ₦33.33
  Show Answer
  The correct answer is D .