Name: ____________________________
The Determination of a Chemical Formula Lab Report Form
Pre-Lab Questions
1.
What does the term “hydrated crystal” mean?
2. Describe, in detail, how one would determine the mass percentage of water in a hydrated crystal:
3. Define the Law of Definite Proportions:
4. Define the Law of Multiple Proportions:
5. Define the term empirical formula:
6.
In step 9 of our procedure, we place a piece of aluminum wire into our copper chloride solution. What
category of chemical change does this reaction follow? Would a piece of silver wire work as well?
Defend your reasoning.
7.
Describe at least 3 physical changes performed in this experiment.
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8. Complete the missing information in the following data table, and use the data to answer the
following questions. (next page)
1.
Mass of crucible
15.772 g
2. Mass of crucible and hydrated sample
16.872 g
3. Mass of hydrated sample
4. Mass of crucible and anhydrous crystal
16.642 g
5. Mass anhydrous crystal
6. Mass of water evolved
7. Mass of empty watch glass
8.234 g
8. Mass of watch glass and copper
8.634 g
9. Mass of copper
A.
Calculate the number of moles of water in the hydrated crystal. SHOW WORK
B. Calculate the number of moles of copper in the sample of copper chloride. SHOW WORK
C. Calculate the moles of chlorine in the sample of copper chloride. SHOW WORK
D. Write the proper chemical formula for the compound that you tested. SHOW WORK
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Experimental DATA TABLE
1. Mass of crucible (g)
2. Mass of crucible and hydrated sample (g)
3. Mass of hydrated sample (g)
4. Mass of crucible and dehydrated sample (g)
5. Mass of dehydrated sample (g)
6. Mass of water evolved (g)
7. Mass of empty watch glass (g)
8. Mass of watch glass and copper (g)
9. Mass of copper (g)
DATA ANALYSIS
1. How many moles of water were in your sample of copper chloride hydrate?
2. How many moles of copper were in your sample of copper chloride?
3. How many moles of chlorine were in your sample of copper chloride?
4. Write the proper chemical formula for the compound that you tested.
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