SIMULATION

SIMULATION CHEM 143: OXIDATION – REDUCTION TITRATION, LAB SIMULATION This week in lab you will not need to a2end the usual lab mee4ng 4mes. Instead you will be directed to a computer simula4on of a redox 4tra4on. Some4me during the week you need to log into this web site and perform the three different 4tra4ons. I highly encourage you to go to your regular lab 4me and work on this lab there as your TA will be there for assistance if needed. h2p://group.chem.iastate.edu/Greenbowe/sec4ons/projecDolder/flashfiles/redoxNew/ redox.html The small tab on the leH of that page that reads “1. Select the Reac4on” allows you to select the 4tra4on system to study. You will be assigned random concentra4ons of the oxidizing and reducing agent solu4ons (one in the bure2e and one in the receiving flask). AHer those values appear, you may use your cursor to slide the volume bar to add 4trant in large volumes. As you get close to the equivalence point (as will be noted in the changing colors in the receiving flask) you should switch to the bu2on to add volume in 0.020 mL increments un4l the color in the flask just barely remains. A good plan is to perform a “scout” 4tra4on where you quickly add 4trant with no inten4on of hiWng the exact equivalence point, but just get close so you will know the volume where you must go very slow (use the bu2on instead of the slider) when you use the “Repeat” bu2on to do another trial with the same concentra4ons. If you hit the “Reset” bu2on your concentra4ons will change and you will need to do another “scout” 4tra4on. Use the data tables provided to record all per4nent data for each of the three 4tra4on simula4ons. Show the calcula4ons, and answers, that provide the correct molari4es of each of the solu4ons in the flasks. Answer the discussion ques4ons that follow the data table and calcula4ons. Review the chapter on electrochemistry in your textbook if you are struggling with the content in the discussion ques4ons. If you encounter technical difficul4es try using the Help Center computers. Contact your TA about any chemical or lab write up clarifica4ons. KMnO4 + Fe2+ * show your calcula4ons -- use the stoichiometry from the balanced equa4on and the general 4tra4on equa4on: K2Cr2O7 + Sn2+ * show your calcula4ons -- use the stoichiometry from the balanced equa4on and the general 4tra4on equa4on: DATA TABLE: M KMnO4 Vol KMnO4 needed Vol Fe2+ sample * M Fe2+ M K2Cr2O7 Vol K2Cr2O7 needed Vol Sn2+ sample * M Sn2+ I2 + S2O3 2- * show the calcula4ons -- use the stoichiometry from the balanced equa4on and the general 4tra4on equa4on: DISCUSSION: 1. Calculate the oxida4on number for one atom of Mn in the KMnO4 of the first reac4on: _____ 2. Considering the change in oxida4on number of Mn in the product, how many electrons are gained or lost by Mn in KMnO4 when the reac4on is balanced? 3. Briefly discuss a real world applica4on where redox 4tra4ons are used. M I2 Vol I2 sample Vol S2O3 2- needed * M S2O3 2-