Question

How many moles of S are in 35.4 g of (C3H5)2S?

Answer 1

0.310 moles First, look up the atomic weights of the elements involved. Atomic weight carbon = 12.0107 Atomic weight hydrogen = 1.00794 Atomic weight sulfur = 32.065 Molar mass (C3H5)2S = 6 * 12.0107 + 10 * 1.00794 + 32.065 = 114.2086 g/mol Moles (C3H5)2S = 35.4 g / 114.2086 g/mol = 0.309959145 mol Since there's just one sulfur atom per (C3H5)2S molecule, the number of moles of sulfur will match the number of moles of (C3H5)2S which is 0.310 when rounded to 3 significant digits.