The empirical formula of ascorbic acid is C₃H₄O₃. Empirical formula is the smallest whole number ratios of elements in a compound.
<h3>FURTHER EXPLANATION</h3>
To get the empirical formula from mass percent data, the following steps are followed:
- Get the mass percent data for all the elements that make up the compound.
- Assume that there is 100 grams of sample compound. Determine the equivalent masses of each element using the mass percent given.
- Convert the mass of each element to number of moles.
- Divide each calculated mole by the smallest mole value.
- The quotient will be the subscript of the element in the compound. If a decimal is obtained, round off the answers to the nearest whole number. Some exceptions to this are the following decimals: x.25, x.33, x.50, and x.75. When these decimals are obtained, all the subscripts are multiplied by a number that will result in a whole number.
Applying steps 1 to 3 to the problem leads to the pseudoformula C₃₋₄₀₇H₄₋₅₃O₃₋₄₀₆ where equivalent number of moles are written as the temporary subscripts of the elements in the compound.
<u>STEP 4:</u> Divide the moles by the smallest mole value which in this case is 3.406.

STEP 5: Multiply the subscripts by a number that would give the smallest whole number ratio.
Since the decimal is 1.33 it cannot be automatically rounded off to 1. It should be multiplied by 3 to get the smallest whole number.
NOTE: All subscripts must be multiplied by the same factor, 3.

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Keywords: empirical formula, chemical formula