Question

calculate

Quantitative Analysis Exp. #5. Determination of Cu % by Using Complexation Reaction 0.01 mol xoSLX Part 1. Preparation of reagents. Preparation of EDTA (0.01M) Dry EDTA in the oven for 2 hours. Dissolve needed grams in a 500 ml volumetric flask. 786/2 PESTA Preparation of known copper solution Place 0.2 8 to 0.25 g of pure Cu wire (or shot) in a 100 ml beaker. Add 15 ml conc. HNO, and 1 ml conc. H,SO. Place a watch glass over the beaker, Boil until dense white fumes of SO, cease. Transfer carefully to a 200 ml volumetric flask, Remember to rinse the watch glass. Dilute to the mark. Part 2. Titration of known sample with EDTA. Place 10 ml of Cu known solution in 250 ml Erlenmeyer flask. Add ammonia/ammonium chloride pH buffer (pH 10) drop-wise until the solution turns completely blue and the precipitate first formed dissolves. Add about 100 ml deion buffer if solution becomes cloudy. Add 1 tablet of murexide indicator and titrate with EDTA until color changes from yellow (green) to deep violet. If the volume of EDTA is less than 10 ml, repeat using 25 ml aliquot of known solution. Repeat titration 4 times, Part 3. Titration of unknown sample with EDTA. Weigh 0.5 to 0.6 grams of unknown into a 200 ml vol. flask. Add 30 mL of 1:5 nitric acid. Heat until all particles are dissolved. Dilute to the mark. Place 25 mL of Cu unknown solution in 250 ml Erlenmeyer flask. Add ammonia/ammonium chloride pH buffer (pH 10) drop-wise until the solution turns completely blue and the precipitate first formed dissolves. Add 1 tablet of murexide indicator and titrate with EDTA until color changes from yellow (green) to deep violet. If the volume of EDTA solution is less than 10 ml use a larger aliquot of your unknown solution Repeat titration few times. hollow but the color at the startinpoint of the

Answer 1

To prepare 0.01M , 500mL EDTA solution . Molarity mass Molar moss x Volume 0.0 mass molt 292.24 x glmoL 500 L Molar mass of EDTA = 29 mass = ord x 292.24 x 500k I mot 9. paol y mot Coo mass = 1.46129] when NOTE: You go to lab See 1st the bottle of EDTA . Whether it is 292.24 EDTA Disodium salt of EDTA Juse 336 g/mol (molar mass) for EDTA & have done calculation. If disodium salt is present in your lab, simply replace 292.24 with 1336 and do the calculation. Because both forms are usually present in the lab. It depends which form have been provided to you by our instructor