Date Performed: July 30, 2012
EXPERIMENT NO. 10
COMPOSITION OF POTASSIUM CHLORIDE

ABSTRACT The aim of the experiment was to look for the percentage composition of the elements present in the decomposition of potassium chlorate (KClO3) and to find out what the residue after heating was. After performing the experiment the researchers found out that there were about 66.14% of potassium chloride (KCl) in KClO3, and they also deducted that the residue was actually KCl.
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Introduction Total mass of the Element/Compound (Part)Total mass of Compound (Whole) × 100
The formula above is the formula used to determine the percentage composition of an
and that the experimental attempt to get the percentage of oxygen in KClO3 had an error of 8.73%.
On the second part of the experiment when 5 drops of dilute (6 M) nitric acid and 5 drops of (0.1 M) silver nitrate solution were added to the solution of the residue and distilled water, potassium chloride solution, and potassium chlorate solution, all of them turned cloudy with white precipitate in them which indicated that chloride ions were present which lead to the deduction that the residue was actually KCl.

1. Mass of crucible + cover | 35.988g. | 2. Mass of crucible + cover + sample before heating | 37.184 g. | 3. Mass of crucible + cover + residue after 1st heating | 37.093 g. | 4. Mass of crucible + cover + residue after 2nd heating | 36.787 g. | 5. Mass of crucible + cover + residue after 3rd heating | 36.779 g. | 6. Mass of original sample=37.184−35.988=1.196 | 1.196 g. | 7. Total mass lost during heating=37.184−36.779=0.405 | 0.405 g. | 8. Final mass of residue=1.196−0.405=0.791 | 0.791 g. | 9. Experimental percent oxygen in KClO3=0.4051.196×100=0.3386×100=33.86% | 33.86% | 10. Experimental percent KCl in KClO3=0.7911.196×100=0.6614×100=66.14% | 66.14% | 11. Theoretical percent oxygen in KClO3=3(16.00)39.10+35.45+3(16.00)×100=48122.55×100=0.3917×100=39.17% | 39.17% | 12. Theoretical percent KCl