Final answer:
To find the number of moles of C3H8 containing a given number of molecules, divide the number of molecules by Avogadro's number.
Step-by-step explanation:
To determine the number of moles of C3H8 that contain 9.25 x 10^24 molecules of C3H8, we can use Avogadro's number. Avogadro's number is approximately 6.022 x 10^23 molecules per mole. So, to find the number of moles, divide the given number of molecules by Avogadro's number:
Moles of C3H8 = (9.25 x 10^24 molecules) / (6.022 x 10^23 molecules/mole) = 15.36 moles C3H8
Therefore, the correct answer is 15.4 moles C3H8.