Please solve q 9?

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1 Answer
Junaid Mirza
Jun 26, 2018

#6.022 × 10^20\ "molecules"#

Explanation:

  • #"1 cm"^3 = 10^-3\ "dm"^3#
  • #"1 mol"# of any gas at STP occupies #"22.4 dm"^3# of volume
  • #"1 mol = 6.022 × 10"^23\ "molecules"#

Volume of dinitrogen gas (in #"dm"^3#)

#22.4 cancel("cm"^3) × (10^-3\ "dm"^3)/(1 cancel("cm"^3)) = 22.4 × 10^-3\ "dm"^3#

Number of moles of dinitrogen

#cancel(22.4) xx 10^-3 cancel("dm"^3) × "1 mol"/(cancel(22.4) cancel("dm"^3)) = 10^-3\ "mol"#

Number of molecules

#10^-3 cancel"mol" × (6.022 × 10^23\ "molecules")/(1 cancel"mol") = 6.022 × 10^20\ "molecules"#

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