The objective of this lab is for students to determine the percentage of cobalt oxalate hydrate using the gravimetric analysis. They will also do a redox titration to determine the percentage of oxalate in the compound. After the percentages are calculated, you will determine the percent water by the difference of Oxalate and Cobalt from %100.
Determination of Cobalt
1. Weigh 0.3 g of solid cobalt oxalate hydrate (from lab 8) on a balance then place it in a preweighed crucible.
2. Place the crucible on a hot plate, and heat the crucible until the substance turns black.
3. Then allow the substance to cool inside the crucible, and weigh the residue inside the crucible. …show more content…
After conducting this lab, we found the percents of Cobalt, Oxalate, and Water in Cobalt Oxalate Hydrate. Cobalt composed of 40.3%, Oxalate composed of 55.1%, and we calculate the composition of water by subtracting 40.3 by 55.1 and which gave us 4.6. After determining the composition of these elements and compounds, we had enough information to calculate the empirical formula: Colbat :
This was the method used to calculate the empirical formula of Cobalt Oxalate Hydrate. Compared to the actual formula, we were pretty close. Sources of errors might have occurred when conducting this experiment. Errors might have occurred in the product, Cobalt Oxalte Hydrate, during the synthesis lab. The product could contaminations and could have been unpurified. Also, during the experiment, error could have been caused from the burning of the Cobalt Oxalate Hydrate in the crucible. We might have exceed the time and the temperature when heating the product to obtain Cobalt Oxalate. Other major factor could have been derived during the titration process. Determining the endpoint sometimes becomes difficult and can be a cause of error. Other than that, this lab was very successful and …show more content…
In order for us to determine the composition of Cobalt, we used the gravimetric analysis. Gravimetric analysis describes a set of methods in analytical chemistry for the quantitative determination of an analyte based on the mass of a solid. It is a technique in which the amount of an analyte can be determined through the measurement of mass.
In addition to gravimetric analysis, it is a method based on the isolation of the desired constituent in pure form or in some combined form from a sample, and weighing the isolated constituent. Similarly thermal decompositions institutes similar components. Thermal decomposition is a method for hydrates to commonly lose all or part of their water when heated. We used this method to decompose Cobalt Oxalate Hydrate into Cobalt Oxalate. Then we calculated the mass of Cobalt by using the molar ratio. Overall this experiment gave an insight on different methods enable to obtain the composition of different elements and compounds from a