Barium Sulfate Gravimetric Method
The objective of this experiment is to use the gravimetric method to determine the concentration of sulfate.
Gravimetric analysis is a method used to determine the mass or concentration of a substance by measuring a change in mass.
To determine the concentration of the sulfate, the precipitation of Barium sulfate is done first by adding the sulfate solution with hydrochloric acid, then heating while stirring it. Next is the washing and filtration of the Barium Sulfate precipitate, using a vacuum pump and a crucible. Lastly, is the drying and weighing of the precipitate by heating the crucible in the oven and cooling it in a desiccator.
The average weight of the precipitate is 0.1602g.
The gravimetric method is useful in finding …show more content…
The solubility of Barium Sulfate can be also determined by the solubility rules whereby most sulfates are soluble in aqueous solutions except for Calcium Sulfate and Silver Sulfate, which are slightly soluble and Barium Sulfate, Mercury(II) Sulfate and Lead(II) Sulfate are insoluble. The weight of the precipitate measured was 0.1602g. However, when compared with other groups, our group’s yield was significantly lower by about 0.0200g.
6.2 Factors Affecting the Results
The weight of the Barium Sulfate precipitate could be caused by factors such as time, impurities and experimental errors. The lab session was only 3 hours long, which is insufficient time for obtaining multiple readings on the precipitation of Barium Sulfate which could give a more accurate and consistent result. Impurities could also affect the weight as not washing the precipitate thoroughly to remove impurities will lead to a lower percentage purity and a greater yield of the precipitate. Experimental errors such as human errors will result in inaccuracies in measuring the actual weight of the precipitate. Misreading instructions and loss of experimental solvents when conducting experiment may give a smaller yield of precipitate. When using the ‘rubber-policeman’ to dislodge the particles in the beaker, some of the precipitate could be stuck on it, hence resulting in a smaller actual yield of the