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Percent Composition of Potassium Chlorate. Experiment #8. Objective. We are going to decompose potassium chlorate by heating it to form potassium chloride and oxygen gas. 2 KClO 3 (s) 2 KCl(s) + 3 O 2 (g). Experimental Procedure. Clean and dry 2 crucibles. Heat crucible
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Percent Composition of Potassium Chlorate Experiment #8
Objective • We are going to decompose potassium chlorate by heating it to form potassium chloride and oxygen gas. • 2 KClO3(s) 2 KCl(s) + 3 O2(g)
Experimental Procedure • Clean and dry 2 crucibles. • Heat crucible • This insures that anything that in the crucible which might change mass on heating will do so before you begin the experiment. • Put weighed crucible on the ceramic pad. • This keeps it from breaking and reminds you that it is hot!!! • Start heating your second cleaned crucible.
Heating crucible You may heat the crucible either with our without the lid, just make sure that you weigh it the same way every time.
Experimental Procedure • Weigh the heated crucible. • Record the data on your data sheet in ink!! • Add 1.0 – 1.5 g of KClO3 to the crucible and reweigh. • Don’t more than 1.5 g- it will to long to decompose. • Be sure to get KClO3, not KCl! • Remove 2nd crucible from heat and allow to cool
Experimental Procedure • Begin to heat the 1st crucible containing the KClO3. • Heat gently at first. • OK to heat either with or without lid. • KClO3 will melt and begin to bubble. • Be careful not to lose any of your KCl. If you see white smoke, it is KCl you are losing! • Once all bubbling has stopped, heat over a hot flame for about 5 minutes.
Experimental Procedure • Remove 1st crucible from heat and allow to cool while you heat the second crucible. • Weigh the cooled crucible and record the mass. • Reheat the crucible a second time for about 5 minutes over a hot flame, cool and reweigh. If the mass has changed less than 0.05 g you are done. Otherwise, do a third heating.