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 1621: Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains Options:
  A) water vapour
  B) oxygen
  C) carbon (IV) oxide
  D) rare gases
  Show Answer
  The correct answer is D .
• Question 1622:

  Which of the following statements is true for strong electrolytes?

  Options:
  A) They do not conduct electricity in the molten state
  B) They completely dissociate into ions in solution
  C) They are non-polar substances
  D) They partially dissociate into ions in solution
  Show Answer
  The correct answer is B .
• Question 1623: 20.00 cm ³ of a solution containing 0.53 g of anhydrous Na₂CO₃ in 100 cm³ requires 25.00 cm³ of H₂SO₄ for complete neutralisation. The concentration of the acid solution in moles per dm is [H =1, C = 12, O = 16, Na =23, S = 32] Options:
  A) 0.02
  B) 0.04
  C) 0.06
  D) 0.08
  Show Answer
  The correct answer is B .
• Question 1624: Which of the following is physical change? Options:
  A) Burning kerosene
  B) Freezing ice cream
  C) Exposing white phosphorus
  D) Dissolving calcium in water
  Show Answer
  The correct answer is B .
• Question 1625: Water for town supply is chlorinate to make it free from Options:
  A) bad colour
  B) bacteria
  C) temporary hardness
  D) permanent hardness
  Show Answer
  The correct answer is B .
• Question 1626:

  If one mole of aluminium contains 6 x 10²³ atoms of aluminium, how many atoms are contained in 0.9g of aluminium?

  (Al = 27)

  Options:
  A) 1.0 x 10²¹
  B) 6.6 x 10²¹
  C) 2.0 x 10²²
  D) 1.0 x 10²²
  E) 5.4 x 10²³
  Show Answer
  The correct answer is C .
• Question 1627:

  The process or act of extracting a metal from its ore and refining it is called?

  Options:
  A) Extraction
  B) Metal mining
  C) Mettallurgy
  D) Prospecting
  Show Answer
  The correct answer is C .
• Question 1628: If the relative molecular mass of an element is not a whole number, it can be deduced that the element is Options:
  A) Naturally radioactive
  B) abundant in nature
  C) a transition metal
  D) an isotopic mixture
  Show Answer
  The correct answer is D .
• Question 1629: The component of an atom that contributes least to its mass is the Options:
  A) proton
  B) nucleus
  C) neutron
  D) electron
  Show Answer
  The correct answer is D .
• Question 1630:

  Using the metal activity series, the metal that can liberate hydrogen gas from steam is?

  Options:
  A) iron
  B) copper
  C) tin
  D) lead
  Show Answer
  The correct answer is A .