Synthesis and Characterization of Cobalt III Coordination Compounds Procedure Determination the Molar Mass of the Cobalt Compound 1 0 15g of compound J and compound D were placed in separate 250 mL Erlenmeyer flasks and labeled 2 0 2 grams of oxalic acid two boiling beads and 10 mL of 3 M H2SO4 were added to each flask 3 In the fume hood the solutions were brought to a boil while keeping the level of the solution in the flasks even This was done until the foam in produced by the oxalic acid subdued 4 Once the flasks cooled 0 2 grams of oxalic acid were added to each flask 5 The walls of the flasks were rinsed with deionized water 6 The solutions were brought to a boil and heated until the foaming subsided Note that the solution was lavender at this point 7 The solutions were cooled until the SO3 fumes cleared 8 50 mL of deionized water were used to rinse the inside walls of each flask 9 The flasks were reheated to their boiling points and swirled until the crystals completely dissolved 10 Each solution was diluted to 100 mL with deionized water and was allowed to cool 11 The solution containing compound J was quantitatively transferred to a 250 mL volumetric flask and diluted to the mark with deionized water 12 The solution containing compound J was mixed well 13 10 0 mL of the solution containing compound J was transferred using a pipette into a clean 100 mL flask 14 10 0 mL of 50 NH4SCN and 50 0 mL of 95 ethanol was added to the solution containing compound J 15 The solution containing compound J was diluted to the mark using deionized water and mixed by inversion 16 The solution containing compound J was placed in a clean dry 400 mL beaker that was labeled standard Co SCN 42 17 The standard Co SCN 42 was covered with Parafilm 18 Steps 11 through 17 were repeated with the flask containing the unknown solution The second 400 mL beaker was labeled unknown instead 19 The Spec 20 was turned on and allowed to warm up for at least 15 minutes 20 The solution of 2 mL of 50 NH4SCN 8 0 mL of deionized water and 10 mL of 95 ethanol 21 This solution was used to blank the Spec 20 22 The wavelength was set to 621 nm 23 The absorbency of the solutions was recorded using the Spec 20 Determination of the Non Amonia Ligands 1 0 2 grams of compound J and D were weighed out and put in separate 100 mL volumetric flasks 2 Both volumetric flasks were filled to the mark with deionized water 3 Cuvettes were filled with known and unknown solutions 4 Deionized water was used to blank the UV UVis spectrophotometer 5 The visible absorption of each solution was recorded with the UV UVis from 360nm to 700nm 6 The infrared spectra was picked up from the TA Determination of the Charge of the Complex Ion Exchange 1 The ion exchange column was rinsed with three portions of 25 mL deionized water Note that the level of water in the column must stay above the level of the resin 2 The column was checked for air bubbles Note that the rinsing process was only considered complete once the pH of the water leaving the column was equal to the pH of the water being poured in 3 0 3 grams of compounds J and D were weighed out and placed in separate 250 mL beakers 4 Each solution was dissolved in 100 mL of deionized water 5 The unknown solution was immediately run through the column at a rate of 10 mL per minute 6 The effluent was collected in a clean 250 mL Erlenmeyer flask 7 When the level of the solution approached the top of the resin the column was rinsed with three 25 mL portions of water Each time it was collected in the same 250 mL flask as the unknown 8 The pH of the column was checked again 9 Steps 5 through 7 were repeated with the compound J standard solution 10 The concentration of the NaOH was calculated by manually titrating the effluent from the standard compound using phenolphthalein as the indicator 11 The unknown solution was carefully titrated using the same indicator and the standardized NaOH solution 12 The charge on the complex ion in the unknown compound was calculated according to the stoichiometric relation between the moles of acid produced and the moles of unknown compound run through the column Determination of the Number of Ammonia Ligands 1 The HCl solution was standardized using the standardized NaOH solution Note phenolphthalein was used as the indicator 2 The distillation apparatus was assembled according to the diagram on page 92 of the Lab Manual 3 The receiver was composed of exactly 50 0 mL of the standardized HCl solution This rested in a 1 liter beaker containing as much ice as could surround the flask 4 The Erlenmeyer flask used to receive was supported by a small inverted beaker Also the 500 mL flask was supported by a rink and pad so that the hot plate fit well under it 5 The bent rubber piece was aligned so that it extended to the bottom of the HCl solution and did not touch it 6 0 15 to 0 2 grams of the unknown compound was weighed out 7 This sample was quantitatively transferred to the 500mL flask and dissolved in 100 mL of deionized water Without mixing 2 boiling chips and 10 mL of 19 M NaOH were added 8 The stopper was quickly put back on 9 The mix was swirled 10 The top of the receiving flask was sealed with aluminum foil so that gas would not escape 11 Note it is very important to have the receiving flask completely surrounded by ice If it is not cold ammonia gas will escape 12 A 25 mL pipette was used to remove water from the beaker as the ice melted Note that the ice was replaced as needed and that it was piled on the flask at all times 13 The basic solution containing the unknown was heated to its boiling point on the hot plate Note that 250oC was sufficient to boil the solution slowly Also note that the solution was not boiled too vigorously because this would force the gas out of the tube faster than the HCl could absorb it 14 The solution was allowed to continue boiling for 20 to 25 minutes Note that all the water from the flask was not allowed to boil off 15 The tube was removed from the HCl before turning off the flame If the hot plate was turned off first or the hot plate temperature was reduced during the procedure the HCl solution would have been drawn back into the 500 mL flask 16 The glass tubing was washed into the HCl solution 17 The solution was brought to room temperature 18 The solution in the receiving flask was titrated with the standardized NaOH Note bromcresol green …