The empirical formula is C₂H₄O₃.
We must calculate the masses of C, H, and O from the masses given.
Mass of C = 32.75 g CO₂ × (12.01 g C/44.01 g CO₂) = 8.9372 g C
Mass of H = 13.4 g H₂O × (2.016 H/18.02 g H₂O) = 1.5067 g H
Mass of O = Mass of compound - Mass of C - Mass of H
= (28.30 – 8.9372 – 1.5067) g = 17.856 g
Now, we must convert these masses to moles and find their ratios. If the ratios are not integers, we multiply them by a number to make them close to integers.
From here on, I like to summarize the calculations in a table.
Element m/g n/mol Ratio ×2 Integers
C 8.9372 0.74415 1 2 2
H 1.5067 1.4948 2.0086 4.0174 4
O 17.856 1.1160 1.4997 2.9994 3
The empirical formula is C₂H₄O₃.
