Question #e980d

1 Answer
Dec 2, 2016

Answer:

#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.