The Dehydration of a Bluestone
To determine the value of X in CuSO4 • xH2O.
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.
The solid was in a blue solid crystal form.
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.
Mass of Crucible
Mass of crucible and CuSO4 •xH2O
Mass of Crucible and anhydrous CuSO4
Calculations ------ Molar Mass of Copper Sulphate -> 64.0+32.1+16*4 = 160.1 g/mol Mass of Crucible
Mass of Crucible and Solid
Mass of Crucible and Anhydrous Solid
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
Mass of Water Lost
1.13 g – 0.70 g = 0.43 g
# of moles of CuSo4
15.52 – 14.82 = 0.70
0.70/160.1 = 0.044 mol
# of moles of Water
0.43 / 18 = 0.024 mol
Amount of water per mol of CuSO4...
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