Elizabeth Laba
Joel Aguilar
Determining the Formula of a Hydrate.
5/7/12
Purpose:
To determine the formula of a hydrate.
Hypothesis:
If the copper sulfate hydrate is weighed, then heated to drive off the water, then the
differences in the masses can be used to determine the formula.
Materials:
Hot Plate, Copper Sulfate Hydrate, Tongs, Scale, Evaporating dish, Safety equipment
Procedures:
Gather materials. Take sample of copper sulfate, crush with mortar and pestle. Record mass.
Then, heat sample of copper sulfate hydrate for 5 minutes, cool, and record mass. Heat sample
for another 5 minutes, cool and record mass. Then keep on heating until you have a constant
mass. Record all data. Subtract initial mass from ending mass to determine mass of water in the
hydrate.
Data and Observations:
Weight of evaporating dish: 32.93
Weight of evaporating dish with Copper Sulfate Hydrate: 43.27
First time heated weight: 41.06
Second time heated weight: 40.93
Third time heated weight: 40.01
Analysis and Calculations:
CuSO4 X xH2O -> CuSO4 + xH2O
Hydrous–Anhydrous
10.34–7.08=3.26g
Moles CuSO4
7.08g/240=0.0295m
Moles H2O
3.26/18=0.1811m
Moles H2O / Moles CuSO4
0.1811111 / 0.0295 = 6.1393597
6 moles
%Error = 20 %
Conclusion:
Our hypothesis was proven. This experiment went by very easy and there was no mistakes made.
The experiment was very simple, but it was interesting. Everyone had to share hotplates so things
sometimes got confusing, but everything turned out well.
References:
Google.com, Wikianswers.com, Reference Table