Coordination Chemistry 1 Overview Getting Started Techniques Procedure FAQ Full Lab Manual Introduction & Goals Chemistry & Background Key Questions Prelab Problems Safety Procedure In Your Write-up Experiments Index ChemLab Home		Synthesis Procedure Start by weighing 3.6 g of Co(NO3)2⋅6H2O and 2.5 g of NH4NO3 on a top-loading balance. Record the masses, and place the solids in a 400 mL beaker. Hot water is preheated for you in a water bath, complete with a small beaker to use as a dipper. Add no more than 10 mL of hot water to the solids in your beaker, and swirl until the solids are completely dissolved. Place the beaker on a stir plate in the hood, and add 40 mL of 6 M ammonia. Over a period of about 30 min, add 25 mL of 3% H2O2 in small ammounts. Use a dropper while stirring the solution. Add a total of 15 mL during the first 15 minutes and a total of 10 mL during the final 15 minutes. After the solution stops bubbling, slowly and carefully add 30 mL of 16 M HNO3, and let the solution cool for 10 min. While you are waiting, measure an amount of ethanol that is approximately equal to the volume of your reaction mixture. Add the ethanol to the reaction mixture and watch for precipitate to form. If precipitate does not become visible, talk to your TA, and review your procedure up to this point. Collect the solid product using vacuum filtration. For details, see the Vacuum Filtration page in the Techniques section of the site. Recrystallization Procedure After weighing your crude product, transfer it to a beaker, and dissolve it in a 1 M solution of ammonia which you make from the 6 M solution in the lab. Place your beaker in the hot-water bath, and stir with a glass rod until the solid dissolves completely. Heat in the water bath for a full 5 min. Cool the beaker in an ice bath, being careful that the beaker does not tip as the ice melts. Monitor the temperature of your solution, and cool to 5 °C. When the solution reaches this temperature, add 16 M nitric acid dropwise to neutralize the ammonia used to dissolve your crude product. Add a 25% excess of acid, and test with pH paper to confirm a strongly acidic pH. Again, collect the solid product using vacuum filtration. Allow the vacuum filtration apparatus to suck air and solvent through your solid, to help dry it. Transfer the solid to a clean, tared glass vial. A good technique for storing the solid is to cover the vial with a Kimwipe held in place with tape. This will allow your solid to dry before next week, without contamination or spilling. Save your vial in the box for your lab section or give it to your TA. You will need to use it in next week's experiment.
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