Answer:
The sample contains 1.066 x 10^25 carbon atoms.
Explanation:
Each molecule of C3H8 contains 3 carbon atoms. Therefore, for however many molcules of C3H8 you have, there will be 3 times as many C atoms. You are told you have 5.9 moles of C3H8, so you have 3 times as much, 3 x 5.9 = 17.7 moles of carbon atoms.
If you want to know how many actual atoms you have, multiply the moles by Avogadro's number:
17.7 x 6.022 x 10^23 = 1.066 x 10^25 carbon atoms
