Indirect Gravimetric Determination

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Purpose:
The purpose of this experiment is to determine the number of moles of water molecules of crystallization of a sample of hydrated Barium Chloride. This can be calculated using Gravimetric Analysis and to indirectly determine the percent composition of a hydrate by taking advantage of its chemical properties. Introduction:

Gravimetric procedures are analytical methods in which the results are determined from the masses of starting materials and products. These methods differ from volumetric procedures in which the calculations are based on the volumes of standardized solutions used in the procedure.

One of the simplest gravimetric procedures involves the heating of a weighed sample to drive off a volatile component. The difference in mass before and after heating provides the mass of the volatile component. Hydrates are examples of compounds that would display this behavior. If the formula of the hydrate is known, the percentage of hydrate in a mixture can be determined. Equipment/Materials:

ounknown mixtureanalytical balance
ocrucible tongs
obunsen burner clay triangle

Caution:
Wear eye Protection and if any chemical splashes in 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.
Procedure:
All absorbed moisture was removed from the empty crucible by heating on a pipe-clay triangle over a blue Bunsen burner flame for about 10 minutes and then the crucible was lifted with clean tongs and allowed to cool in a desiccator (which contained silica gel that absorbed moisture). Once cool, the empty crucible was weighed and approximately 2-3g of Hydrated Barium Chloride was added to the crucible. The crucible and contents were then weighed on a balance and a note of the mass was taken. The crucible...
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