The law of definite proportions states that different samples of a pure compound always contain the same elements in the same proportions by mass. For example, sodium chloride always contains 60.7 % chlorine and 39.3 % sodium by mass.
A sample of potassium chlorate (KClO3) will be thermally decomposed. This process will release the oxygen molecules and leave the compound potassium chloride (KCl). Suppose you will then calculate the decrease in mass due to lost oxygen in order to verify the theoretical mass percent of oxygen in the potassium chlorate by using the experimental and theoretical values, discuss how to come up with the values after the experiment.
Determine the average mass percent of oxygen in potassium chlorate using your two experimental values. Is it lower than either of your individual experiments How well do your experimental results match the theoretical value?