Gravimetric Determination Essay

Lab 2. The Gravimetric Determination of Chloride in a Soluble Sample
Introduction:
For the experiment you will obtain an unknown sample, containing chloride ion, and perform the gravimetrical procedure using the sample of the analyte. An analyte is a chemical constituent that is determined from analytical techniques. The technique used in the experiment is the gravimetric determination analysis which is a method of quantitative chemical analysis in which the key constituent being sought after is converted to a substance that can be separated from the remaining sample. A common method for determining chloride ions involves isolating the silver chloride precipitate via filtration, determining its mass, and using stoichiometry to calculate the percentage of chloride in an impure sample of unknown chloride. Since the unknown chloride is soluble in water, the percent chloride can be analyzed through the addition of an aqueous solution, silver nitrate, which can form a precipitate with the aqueous chloride.

Experimental:
In order to accomplish this experiment we’ll need to obtain the materials and chemicals that are required. Material that are required to attain are the sintered glass filtering crucibles (3), desiccator (a drying chamber that keeps materials in the absence of air or in the presence of a drying agent.), analytical balance, hot plate, aluminum foils, 400ml beakers (3), vacuum filter flask, the waste container and turn on the lab convection oven at 110°C. The chemicals required: 3 grams of unknown impure sample of analyte (chloride), 6M HNO3, concentrated HNO3, 6M NH3 (minimum of 10 mL), 0.2 M AgNO3 (minimum of 300mL).

Results:
Equations

Mean /average (¯X) = (∑▒x)/n
Standard deviation s= √((∑▒〖(x_i- x ̅)〗^2 ...

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...eral situations where the only suitable analytical technique is the gravimetric method. There were several sources of error in this experiment that must be considered. If any contaminants got into any of the reagents involved in this experiment, then other reactions would cause other precipitates to form, causing inaccurate mass readings for the supposed silver chloride compound. Possible points of contamination may take place while handling compounds; if tap water was accidentally used (substances in the water would react with silver nitrate); or other contaminants in the original sample. Other sources of error include bad technique. Decomposition from light would also produce low results. A possible source of error could have been due to the crucibles not being cooled enough in the dessicators, which could have affected the masses of the AgCl samples as well.