How many atoms of C are there in 25 g of pentane(C5H12)?

Question

What's the method to finding the answer?

Answer 1

Find the number of moles of pentane, then multiply that answer by 5 since there are 5 carbon atoms in each molecule of pentane:

1) mass of pentane = (12 x 5) + (1 x 12) = 72 amu

25 g / 72 amu = moles C5H12 = 0.35 mol C5H12

multiply # moles by 5 carbons 0.35 mol x 5 C per mol = 1.75 mol C atoms

multiply moles of carbon atoms by 6.02 x 10^23 to find the number of atoms = 1.05 x 10^24 atoms of carbon

Answer 2

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Answer 3

the periodic table.