Question

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H,

Answer 1

Answer:

Molecular formula => C₃H₈O₃

Explanation:

From the question given above, the following data were obtained:

Carbon (C) = 39.12%

Hydrogen (H) = 8.75%

Oxygen (O) = 51.12%

Molar mass of compound = 92.09 g/mol

Molecular formula =?

Next, we shall determine the empirical formula of the compound. This can be obtained as follow:

C = 39.12%

H = 8.75%

O = 51.12%

Divide by their molar mass

C = 39.12 / 12 = 3.26

H = 8.75 / 1 = 8.75

O = 51.12 / 16 = 3.195

Divide by the smallest

C = 3.26 / 3.195 = 1

H = 8.75 / 3.195 = 2.7

O = 3.195 / 3.195 = 1

Thus, the empirical formula is CH₂.₇O

Finally, we shall determine the molecular formula of the compound. This can be obtained as follow:

Empirical formula = CH₂.₇O

Molar mass of compound = 92.09 g/mol

Molecular formula =?

Molecular formula = Empirical formula × n

Molecular formula = [CH₂.₇O]ₙ

92.09 = [12 + (2.7×1) + 16] × n

92.09 = 30.7n

Divide both side by 30.7

n = 92.09 / 30.7

n = 3

Molecular formula = [CH₂.₇O]ₙ

Molecular formula = [CH₂.₇O]₃

Molecular formula = C₃H₈O₃