An alcohol is 68.84 % C and 4.962 % H by mass. The rest is oxygen. What is the empirical formula of the alcohol? Enter the elements in the order C, H, and then O.

The empirical formula is C₇H₆O₂.

Assume that you have 100 g of the compound.

Then you have 68.84 g C and 4.962 g H.

Mass of O = (100 - 68.84 - 4.962) g = 26.20 g O.

Now, we must convert these masses to moles and find their ratios.

From here on, I like to summarize the calculations in a table.

Element Mass/g Moles Ratio * 2 Integers

C 68.84 5.732 3.501 7.001 7

H 4.962 4.923 3.006 6.012 6

O 26.20 1.638 1 2 2

The empirical formula is C₇H₆O₂.