How do you calculate empirical formula of a compound?
If a question gives you a compound showing percentages , you have to find the simplest ratio of atoms in the compound.
For example, a question wants you to find the empirical formula that contains 11% hydrogen and 89% oxygen.
First step, assume that these substances add up to 100 grams in masses. Assume that 100 grams contains 11 grams of hydrogen and 89 grams of oxygen.
Second step, use
number of moles of hydrogen = 11 grams
number of moles for oxygen = 89 grams
Third step, divide all number of moles by the smallest.
Hydrogen (H): 11
Oxygen (O): 5.56
*round it off to nearest whole number, then assign it as subscripts.
Therefore the empirical formula is