Question

Question #e980d

Answer 1

`7.54 * 10^(-15)"moles"`

Explanation:

The relationship between number of moles and number of molecules is given by Avogadro's constant, which essentially acts as the definition of the mole

`color(blue)(ul(color(black)("1 mole" = 6.022 * 10^(23)"molecules")))`

So, you know that you need to have exactly `6.022 * 10^(23)` molecules of carbon dioxide in order to have `1` mole of this molecular compound.

The problem provides you with a sample of

`454,000,000 = 4.54 * 10^8`

molecules of carbon dioxide, so use Avogadro's constant as a conversion factor to convert the number of molecules to number of moles

`4.54 * 10^9 color(red)(cancel(color(black)("molecules CO"_2))) * "1 mole CO"_2/(6.022 * 10^(23)color(red)(cancel(color(black)("molecules CO"_2))))`

`= color(darkgreen)(ul(color(black)(7.54 * 10^(-15)"moles CO"_2)))`

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