Question

A key ingredient of nail polish remover is found to have the following percentage composition by mass: 62.0% carbon, 10.4% hydrogen, and 27.5% oxygen. If its molar mass is 58.1g/mol, what is its molecular formula?

Answer 1

Answer:

C3H6O

Explanation:

To get the molecular formula, we are going to divide the percentage compositions by the atomic masses. The atomic masses of carbon, hydrogen and oxygen are 12, 1 and 16 respectively.

The division goes on as follows:

C = 62.0/12 = 5.17

O = 27.5/16 = 1.72

H = 10.4/1 = 10.4

We go on to divide by the smallest which is that of the oxygen which is 1.72

C = 5.17/1.72 = 3

O = 1.72/1.72 = 1

H = 10.4/1.72 = 6

The empirical formula is thus C3H6O

Now, to get the molecular formula.

[C3H6O]n = 58.1

( 3(12) + 6(1) + 16)n = 58.1

58n = 58.1

n = 1

The molecular formula is thus C3H6O