Q6. The manufacturer supplying concentrated ethanoic acid for the production of vinegar als

supplied other acids. The label had come off a batch of one of these other acids.

A sample of this unknown acid was analysed and found to contain 54.5% of carbon and 9.10% OL

hydrogen by mass, the remainder being oxygen.

CHO

(a)

Use these data to calculate the empirical formula of the unknown acid.

Show your working.

The problem gives us the percentages for carbon and hydrogen in the unknown acid:

54.5 % carbon

9.10 % hydrogen

The difference until 100 % is oxygen:

36.4 % oxygen

Now we may calculate the empirical formula of the unknown acid:

First we divide each percentage by the atomic mass of each component:

carbon = 54.5 / 12 = 4.54

hydrogen = 9.1 / 1 = 9.1

oxygen = 36.4 / 16 = 2.28

Now we divide the answers to the smallest number, which is 2.28:

carbon = 4.54 / 2.28 = 2

hydrogen = 9.1 / 2.28 = 4

oxygen = 2.28 / 2.28 = 1

Now the empirical formula for the acid will be:

C₂H₄O₁

And molecular formula:

(C₂H₄O₁) ₓ, but here we do not have enough information to determine unknown "x".