Determination of Cobalt Oxalate Hydrate

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Determination of Cobalt Oxalate Hydtrate
Introduction
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. Procedure

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. (This will give the mass percent of cobalt.) 4.Repeat all these steps again, to acquire the results for Trial 2. Determination of Oxalate

1.Weigh 0.15g of Cobalt oxalate hydrate, and place it in a 250mL Erlenmeyer flask. 2.Add 25ml of 1M H2SO4 solution to the flask
3.Place the flask on a hot plate, stir to dissolve the substances in the flask, heat the solution until it reaches 60 C. 4.Then titrate the solution with Potassium permanganate, wait for a color change in order to determine the end point. 5.Repeat all these steps again, to acquire the results for Trial 2. Data/Results

Determination of Cobalt
Trial 1Trial 2
Mass of Crucible and Cobalt Oxalate20.245g19.721g
Mass of Crucible19.945g19.421g
Mass of Cobalt Oxalate0.30g0.30g
Mass of Crucible and Residue19.95g19.87g
Mass of Crucible19.945g19.721g
Mass of Residue0.149g0.131g
% Co in Cobalt Oxalate37.0%43.6%
Average % Co40.3%
Determination of Oxalate
Mass of Container and Cobalt Oxalate128.44128.44
Mass of Container128.296128.296
Mass of Cobalt Oxalate0.1560.151
Final reading of KMnO4 buret31.70mL30.70mL
Initial reading of KMnO4 buret50.00mL50.00mL
Volume of KMnO4 solution required18.30mL19.30mL
%...
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