The empirical formula or simplest formula gives the smallest whole number ratio of atoms present in a compound. This formula gives the relative number of atoms of each element in the compound.
To find the Empirical Formula of a compound we must find the whole number ratio of atoms of the elements in a sample of the compound. When the numbers in the ratio are reduced to their lowest terms, until they have no common divisor, they are the subscripts in the empirical formula.
Empirical Formula can be calculated by the following steps.
1. Express the mass of each element in grams using the definite staring
quantity. Assume a starting value if not given.
2. Using each element’s molar mass, convert the grams for each element into moles. This will result in the number of moles of atoms for each element in the quantity assumed in step 1.
3. Divide each result obtained in step two by the smallest values. If the values obtained are whole numbers, use them as subscripts and write the empirical formula.
4. Multiply the values obtained in step 3 by the smallest number that will convert them to whole numbers. Use these whole numbers as the subscripts in the empirical formula.
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