Question

How would you calculate the empirical formula of acetic acid (${\mathrm{CH}}_3\mathrm{COOH}$)?

Answer 1

• The empirical formula is the simplest possible formula for a compound.
• The molecular formula of ${\mathrm{CH}}_3\mathrm{COOH}$ can be written as ${\mathrm{C}}_2{\mathrm{H}}_4{\mathrm{O}}_2$ .
• The ratios of $\mathrm{C}:\mathrm{H}:\mathrm{O}$ in the formula of Acetic acid are $2:4:2$
• Then divide each of these numbers by a common factor $2$ to convert them into simplest ratio $\mathrm{C}:\mathrm{H}:\mathrm{O}=1:2:1$
• The empirical formula of Acetic acid is then: ${\mathrm{CH}}_2\mathrm{O}$ .

Thus, in this way, we found out that the empirical formula of Acetic acid is ${\mathrm{CH}}_2\mathrm{O}$.