Citric acid, the compound responsible for the sour taste of lemons, has the following elemental composition: C, 37.51%; H, 4.20%; O, 58.29%. Calculate the empirical formula of citric acid. (Type your answer using the format CO2 for CO2.)

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2 answers

First convert each percentage to grams.
37.51g C x (1 mol C/12.01g C)= 3.123 mol C
4.20g H x (1 mol H/1.008 g H)= 4.17 mol H
58.29 O x (1 mol O/16.00 g O)= 3.643 mol O
Since C has the lowest moles divide each mole by the moles of Carbon.
C= 1 mole
H= 1.34 moles
O= 1.167 moles
Then multiple each mole by 3.
The empirical formula is C3H4O3.
The answer should actually be C6H8O7. The other user should have multiplied by 2.