Reasons why some methods do not produce 100% yield
-Errors in weighing
-Rectants have formed some impurities
-Some of the reactants lost (for example as a gas)
-Not all of reactants converted to product
Percentage yield= mass of product formed / maximum mass of product
The empirical formula of a compound or molecule is its elements in the most simple ratio.
To work out the empirical formula
1. Divide mass or % given by Mr of each element.
2. Use the smallest answer, and divide your previous answers by this number.
3.Write the empirical formula as a ratio