The Dehydration of a Bluestone
The Dehydration of a Bluestone
The Dehydration of a Bluestone
February.28.2008
Purpose
To determine the value of X in CuSO4 • xH2O.
Materials
Crucible
Blue Stone
Bunsen Burner
Bunsen Lighter
Test Tube
Water
Rheostat
Clay Triangle
Electronic Balance
Procedure
A clean crucible was taken and weighed on an electronic balance. The mass was then written down. 2g of bluestone was placed in the crucible and weighed. The mass of the blue solid was written down. The crucible was placed on a clay triangle and was heated by the Bunsen burner. When the blue color disappeared, the crucible was left to cool. After the crucible had cooled, the crucible was placed on the electronic balance to be weighed for its final mass of crucible and anhydrous solid. After the mass was written, a small amount of the anhydrous solid was taken and placed in a test tube. Then a few drops of water were added and the reaction was observed and written down.
Observations
Before
The solid was in a blue solid crystal form.
During
As it was heating, the blue solid slowly turned a whitish grayish color.
After
The blue solid had turned a grayish white color and when water was added back to the anhydrous solid it turned blue again.
When the water droplets were added the bottom of the test tube felt hot.
Data
Mass of Crucible
14.82 g
Mass of crucible and CuSO4 •xH2O
15.95 g
Mass of Crucible and anhydrous CuSO4
15.52 g
Mass of Crucible
14.82 g
No Calculation
Mass of Crucible and Solid
15.95 g
No Calculations
Mass of Crucible and Anhydrous Solid
15.52 g
No Calculations
Mass of CuSO4 • xH2O
15.95 g – 14.82 g = 1.130 g
1.13 g
Mass of CuSO4
15.52 g – 14.82 g = 0.70 g
0.70 g
Mass of Water Lost
1.13 g – 0.70 g = 0.43 g
0.43 g
# of moles of CuSo4
15.52 – 14.82 = 0.70
0.70/160.1 = 0.044 mol
0.0044 mol
# of moles of Water
0.43 / 18 = 0.024 mol
0.024 mol
Amount of water per mol of CuSO4
0.024 mol / 0.0044 = 5.4
X = 5.4
Discussion
How do you know when the copper (2) sulphate has been converted to it anhydrous form?
When