1. Calculate and record the following for the experiment performed with 20g KClO3:

a mass of the crucible with manganese(IV) dioxide (in grams) 88.100g
b mass of the crucible after potassium chlorate has been added (in grams) 108.100g
c mass of the crucible after heating (in grams) 100.267g
d mass of oxygen in sample of potassium chlorate (in grams) [(b) minus (c)] 7.833g
e mass of potassium chloride (in grams) [the mass of the original potassium chlorate added to the crucible minus (d)] 100.167g

2. Calculate your experimental mass percent of oxygen in KClO3 according to:

experimental mass percent of oxygen = [mass of oxygen lost (d)] / (mass of KClO3 added to the crucible)

7.833/108.100 =0.07

3. Using a Periodic Table Find the elements K, Cl and O, and click on each one to find their atomic weights. Use these to calculate a theoretical mass percent of oxygen in KClO3 according to:

theoretical mass percent of oxygen = (mass of 3 oxygen atoms) / (molecular weight of KClO3)

4. Calculate the percent error in the experiment using the experimental and theoretical values of the mass percent of oxygen. The percent error is defined as:

|(experimental value) - (theoretical value)| / theoretical value * 100%

5. How well does your experimental result match the theoretical value? What sources of error may explain the discrepancy?