Answer:
The empirical formula of citric acid is C6H8O7
Explanation:
Step 1: Data given
Suppose the compound has a mass of 100.0 grams
The compound contains:
37.51 % C = 37.51 grams C
4.20 % H = 4.20 grams H
58.29 % O = 58.29 grams O
Molar mass of C = 12.01 g/mol
Molar mass of H = 1.01 g/mol
Molar mass of O = 16.00 g/mol
Step 2: Calculate moles
Moles = mass / molar mass
Moles C = 37.51 grams / 12.01 g/mol
Moles C = 3.123 moles
Moles H = 4.20 grams / 1.01 g/mol
Moles H = 4.16 moles
Moles O = 58.29 grams / 16.00 g/mol
Moles O = 3.643 moles
Step 3: Calculate mol ratio
We divide by the smallest amount of moles
C: 3.123 moles / 3.123 moles = 1
H: 4.16 moles / 3.123 moles = 1.33
O: 3.643 moles / 3.123 moles = 1.17
If we multiply those by 6 we find the coefficients of the empirical formula
C6H8O7
The empirical formula of citric acid is C6H8O7
