1. Assume a 100 g Sample
* This makes the calculations easier, as the percentages directly translate to grams.
* You have 85.7 g of carbon and (100 - 85.7) = 14.3 g of hydrogen.
2. Convert Grams to Moles
* Use the molar mass of each element:
* Carbon (C): 12.01 g/mol
* Hydrogen (H): 1.01 g/mol
* Moles of carbon: 85.7 g / 12.01 g/mol = 7.14 mol
* Moles of hydrogen: 14.3 g / 1.01 g/mol = 14.2 mol
3. Find the Simplest Mole Ratio
* Divide each number of moles by the smallest number of moles (7.14 in this case):
* Carbon: 7.14 mol / 7.14 mol = 1
* Hydrogen: 14.2 mol / 7.14 mol = 2
4. Write the Empirical Formula
* The empirical formula represents the simplest whole-number ratio of atoms in the compound.
* The empirical formula for this hydrocarbon is CH₂.
