Answer
Mass percentage of C = 60.0 %
Mass percentage of H = 13.3 %
Mass percentage of O = 26.7 %
Work Step by Step
Strategy: To calculate the mass percentage of elements in the compound : 1- calculate the Molar mass of the compound 2- Calculate the mass of each element to the Molar mass and express this in percentage.
2 - propanol chemical formula, based on the figure : $C_{3}H_{8}O$
Molar mass $C_{3}H_{8}O$= 3 x 12.0 + 8 x 1.00 + 1 x16.0
Molar mass $C_{3}H_{8}O$ = 60.0 g/mol
Mass percentage of C = $\frac{mass_(3 mole C)}{Molar mass_(C_{3}H_{8}O)}$$\times$ 100%
Mass percentage of C = $\frac{3\times12.0}{60.0}$$\times$ 100%
Mass percentage of C = 60.0 %
Mass percentage of H = $\frac{mass_(8 mole H)}{Molar mass_(C_{3}H_{8}O)}$$\times$ 100%
Mass percentage of H = $\frac{8\times1.00}{60.0}$$\times$ 100%
Mass percentage of H = 13.3 %
Mass percentage of O = $\frac{mass_(1 mole O)}{Molar mass_(C_{3}H_{8}O)}$$\times$ 100%
Mass percentage of O = $\frac{1|\times16.0}{60.0}$$\times$ 100%
Mass percentage of O = 26.7 %