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Chemistry Past Questions and Answers

Topic: The mole concept and Avogadro's number

Jamb Chemistry Questions - The mole concept and Avogadro's number

Question 6:
For a gas, the relative molecular mass is equal to 2Y. What is Y?
  • A The mas of the gas
  • B The vapour density of the gas
  • C The volume of the gas
  • D The temperature of the gas
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Question 7:
A fixed mass of gas has a volume of 92cm3 at 3 oC. When will be its volume at 18 oC if the pressure remains constant
  • A 15.3cm<sup style='font-size: smaller;'>3</sup>
  • B 87.3cm<sup style='font-size: smaller;'>3</sup>
  • C 552.0cm<sup style='font-size: smaller;'>3</sup>
  • D 97.0cm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation
Question 8:
What volume of oxygen is produced from the decomposition of 2 mole of KCIO3 at s.t.p?
[Molar volume of a gas at s.t.p = 22.4 dm3]
  • A 22.4 dm<sup style='font-size: smaller;'>3</sup>
  • B 33.6 dm<sup style='font-size: smaller;'>3</sup>
  • C 44.8 dm<sup style='font-size: smaller;'>3</sup>
  • D 67.2 dm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation
Question 9:
What volume of oxygen is produced from the decomposition of 2 mole of KCIO3 at s.t.p?
[Molar volume of a gas at s.t.p = 22.4 dm3]
  • A 22.4 dm<sup style='font-size: smaller;'>3</sup>
  • B 33.6 dm<sup style='font-size: smaller;'>3</sup>
  • C 44.8 dm<sup style='font-size: smaller;'>3</sup>
  • D 67.2 dm<sup style='font-size: smaller;'>3</sup>
View Answer & Explanation
Question 10:
A compound contains 40.0% carbon 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, find the molecular formula.
[H = 1, C = 12, O = 16]
  • A CH<sub style='font-size: smaller;'>2</sub>O
  • B C<sub style='font-size: smaller;'>3</sub>H<sub style='font-size: smaller;'>6</sub>O<sub style='font-size: smaller;'>3</sub>
  • C C<sub style='font-size: smaller;'>6</sub>H<sub style='font-size: smaller;'>12</sub>O<sub style='font-size: smaller;'>6</sub>
  • D C<sub style='font-size: smaller;'>6</sub>H<sub style='font-size: smaller;'>12</sub>O<sub style='font-size: smaller;'>3</sub>
View Answer & Explanation