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Law of Definite Proportions

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

(a) mass of the crucible with manganese(IV) dioxide (in grams): 53.300g
(b) mass of the crucible after potassium chlorate has been added (in grams): 73.300g
(c) mass of the crucible after heating (in grams): 21.00 degrees C
(d) mass of potassium chloride (in grams): 8.64
(e) mass of oxygen in sample of potassium chlorate (in grams): 65.367g
(f) mass percent of oxygen in potassium chlorate:

2. Calculate a theoretical mass percent of oxygen in KClO3 according to:

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

3. 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%

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

Solution Preview

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

(a) mass of the crucible with manganese(IV) dioxide (in grams): 53.300g

(b) mass of the crucible after potassium chlorate has been added (in grams): 73.300g

(c) mass of the crucible after heating (in grams):
If the mass of potassium chloride is 8.64 g and the mass of crucible is 53.500 g, then, the mass of crucible after heating (that's including potassium chloride) should be 62.14 g (from adding 8.64 g and 53.500 g)

(d) mass of potassium chloride (in grams): 8.64

(e) mass of oxygen ...

Solution Summary

This solution deals with calculating results for an experiment that involves 20 grams of KClO3. This solution also answers why discrepancies might exist in the calculations.

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