Question #f6b8c

1 Answer
Stefan V.
Aug 27, 2017

4.187 * 10^(25)

Explanation:

For starters, you know that each molecule of carbon dioxide, "CO"_2, contains

  • one atom of carbon, 1 xx "C"
  • two atoms of oxygen, 2 xx "O"

This means that every mole of carbon dioxide will contain 2 moles of oxygen atoms.

You can thus say that your sample will contain

34.77 color(red)(cancel(color(black)("moles CO"_2))) * "2 moles O"/(1color(red)(cancel(color(black)("mole CO"_2)))) = "69.54 moles O"

Now, in order to have 1 mole of oxygen atoms, you need to have 6.022 * 10^(23) atoms of oxygen -> this is given by Avogadro's constant.

This means that your sample will contain a total of

69.54 color(red)(cancel(color(black)("moles O"))) * (6.022 * 10^(23)color(white)(.)"atoms O")/(1color(red)(cancel(color(black)("mole O"))))

= color(darkgreen)(ul(color(black)(4.187 * 10^(25)color(white)(.)"atoms O")))

The answer is rounded to four sig figs, the number of sig figs you have for the number of moles of carbon dioxide.

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