Elemental analysis of 50.0000 g of a compound showed that it contained 12.7520 g C, 3.2105 g H, and the rest was S. The empirical formula of this compound is ________.

Question

Quizplus · Accepted Answer

First, we need to find the amount of S in the compound:
Mass of S = Total mass - mass of C - mass of H
Mass of S = 50.0000 g - 12.7520 g - 3.2105 g
Mass of S = 33.0375 g

Next, we need to find the mole ratio of each element in the compound:
moles of C = 12.7520 g / 12.011 g/mol = 1.0629 mol
moles of H = 3.2105 g / 1.008 g/mol = 3.1853 mol
moles of S = 33.0375 g / 32.066 g/mol = 1.0295 mol

Divide each mole value by the smallest of the three, which is 1.0295 mol:
C: 1.0629 / 1.0295 = 1.0317 -> ~1
H: 3.1853 / 1.0295 = 3.0901 -> ~3
S: 1.0295 / 1.0295 = 1

The empirical formula is therefore CH3S, which is closest to choice C: CHS.

Elemental Analysis of 50