Gravimetric determination of water in Hydrated Barium Chloride
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Introduction
Gravimetric determination of water in Hydrated Barium Chloride. Aim: - The aim of this experiment is to determine the number of moles of water molecules of crystallisation of a sample of hydrated Barium Chloride. This can be calculated using Gravimetric Analysis, which involves comparing the mass of the hydrated with the mass of the anhydrous salt. Hydrated Barium Chloride is heated to constant mass. The number of moles of water of crystallisation (n in BaCl2. H2O) can be found by calculating the loss of mass in the sample. Procedure: - All absorbed moisture was removed from the crucible by heating over a Bunsen burner and then by cooling in a dessicator. The crucible was then weighed and approximately 3g of Hydrated Barium Chloride was added to the crucible (this was done wearing gloves and in a fume cupboard). ...read more.
Middle
Hazcon:- Wear eye Protection and if any chemical splashes n your skin wash it off immediately. Barium Chloride is harmful by inhalation and by ingestion or skin contact. Wear Gloves. Hydrated Barium Chloride is crystalline, but the anhydrous salt that is produced is powdery. Avoid raising a dust. Result:- Initial mass of Barium Chloride Initial mass of crucible& Barium Chloride (g) Mass after heating(g) Total mass lost(g) 1st Heating 2nd Heating 3rd Heating 4th Heating 1st Attempt 3.03 25.57 25.19 25.13 25.08 25.08 0.49 2nd Attempt 2.86 25.36 24.93 24.93 0.43 BaCl2.H2O BaCl2 + H2O The hydrated Barium Chloride sample contained about 2.23mol of water molecules per mole. BaCl2.H2O BaCl2 + H2O The hydrated Barium Chloride sample contained about 2.05 mol of water molecules per mole. ...read more.
Conclusion
If soot formed on the crucible its mess would be changed, making the results inaccurate. Dirt could have been transferred from the tongs to the crucible while it was being lifted, again this would affect the mass of the crucible. This error would have been eliminated had clean tongs been used. The Barium Chloride had to be heated to constant mass to ensure that all traces of water had been removed to reduce errors in the calculation. Gravimetric analysis is more accurate than volumetric analysis because the only error in gravimetry should be weighing error so the results are as accurate as the balance used. Improvements could have been made by using a more accurate balance and also by calibrating the balance. ?? ?? ?? ?? Aakanksha Sadekar 1 ...read more.
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