Use the structure to determine the molecular formula, molar mass, and percent by mass of sulfur in this compound.

Question

Use the structure to determine the molecular formula, molar mass, and percent by mass of sulfur in this compound.

molecular formula:?

molar mass:? g/mol

percent by mass of sulfur:? %

Biological studies have found that aqueous solutions containing as little as 28 μg of allicin per milliliter inhibit bacterial growth. Express this amount as the number of moles of allicin per liter of solution.

28 μg/mL=? mol/L

Answer 1

The structure shown has the molecular formula C₆H₁₀OS₂

Molar mass:

6C = 6 x 12.01 = 72.06

10H = 10 x 1.01 = 10.1

1O = 1 x 16.0 = 16.0

2S = 2 x 32.1 = 64.2

molar mass = 162 g / mole

Percent by mass of S:

64.2 g / 162 g (x100%) = 39.6% sulfur

Converting 28 ug / ml to mol / L:

28 ug / ml x 1000 ml / L = 28000 ug / L

28000 ug / L x 1 mg / 1000 ug = 28 mg / L

28 mg / L x 1 g / 1000 mg = 0.028 g / L

0.028 g / L x 1 mol / 162 g = 1.73x10^-4 mol / L