How many grams are there in #1.5 * 10^26# molecules of #CO_2#?
1 Answer
Explanation:
Your strategy here will be to

use Avogadro's number to calculate how many moles of carbon dioxide would contain that many molecules

use carbon dioxide's molar mass to determine how many grams would contain that many moles
As you know, one mole of any substance contains exactly
Notice that you're dealing with more than
More specifically, you'll have
#1.5 * 10^(26) color(red)(cancel(color(black)("molecules"))) * "1 mole CO"_2/(6.022 * 10^(23)color(red)(cancel(color(black)("molecules")))) = 2.491 * 10^2"moles CO"_2#
Now, a substance's molar mass tells what the mass of one mole of that substance is. In carbon dioxide's case, its molar mass is equal to
In your case,
#2.491 * 10^2 color(red)(cancel(color(black)("moles CO"_2))) * "44.01 g"/(1 color(red)(cancel(color(black)("mole CO"_2)))) = "109.63 g"#
Rounded to two sig figs, the number of sig figs you have for the number of molecules of
#m_(CO_2) = color(green)("110 g")#