Download Decomposition of Potassium Chlorate

Name:_____________________________________
Date:________
The Decomposition of Potassium Chlorate
Safety: Wear goggles at all times and be careful not to touch hot equipment.
Purpose: Perform a decomposition reaction, measure
the remaining solid product and compare the
experimental yield to the theoretical yield.
Materials:
Balance
Clay triangle
Ring stand and ring
Bunsen burner
Tongs
Forceps
Clean crucible and lid
**Do not put a hot crucible in cool/cold water.
Procedure:
1. Use tongs to hold clean, dry crucible over flame for 2 minutes. If the crucible appears
to be turning black, adjust the Bunsen burner to prevent this and clean the crucible
before continuing. Allow heated crucible to cool. Do not touch crucible or lid with
your hands after this step. Weigh an empty crucible and cover. Record in data table.
2. Add ~2 grams of KClO3 and partially cover with crucible lid. Record exact mass in
data table.
3. Heat for 15 minutes with equipment set up as shown. The texture of the reactant
should visibly change. Do not lean directly over the crucible.
4. While the potassium chlorate heats, calculate the expected yield of solid product and
write a hypothesis to state the expected mass of KCl.
5. Allow to cool. Handle crucible only with tongs.
6. Reweigh. Record in data table.
7. Calculate the weight of product.
Data Table:
Weight of empty crucible and cover
Weight of crucible, cover and KClO3
sample
Weight of KClO3 sample before heating
Weight of sample, crucible, and cover
after heating
Weight of the sample only- after heating
Rev. 1
Analysis and Results
Show work for credit!
1. Reaction:
Write the balanced chemical equation for this reaction. Include the state of matter.
(For example, KClO3(s) indicates the potassium chlorate is solid phase)
2. Stoichiometric calculations for theoretical yield: (Include the formula for the
product.)
3. Percent Yield:
Percent yield = actual yield
theoretical yield
x 100%
Percent yield = ___________________________
Conclusion
Write a conclusion related to your hypothesis. Explain possible explanations for the
difference between actual and theoretical (expected) yield
Post-Lab Questions
1. Write the balanced equation for the decomposition of sodium chlorate.
2. Write the balanced equation for the decomposition of calcium chlorate.
3. Look at the products of these reactions. How did you know which product was in
the crucible after heating?
Rev. 1