Chem 162 - Lab 4 - Grading: 60 pts Assigned Points 5 5 A....

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Unformatted text preview: Grading: 60 pts Assigned Points 5 5 A. Starting Components (Fract. Crystallization #0) Step 3: Mixture before first crystallization 4.558 g 0.45 g Total mass of the sample mixture 5.006 g % Impurity (% Fe compound in the mixture) 8.95 % 1 (This is your % impurity for Frac Crystallization # 0) Fract. Crystallization #1 Step 7: mass dry filter paper 0.31 g Step 10: 3.97 g 3.669 g 1 80.50 % 1 Step 11: 0.099 g B. Fract. Crystallization # 2 (Re-crystallization) Step 6: mass dry filter paper 0.31 g Step 8: 1.56 g 1.253 g 1 27.49 % 1 Step 9: 0.286 g Name: Alice Meng-Ju Hsieh Qz Section: AA Lab Partner: Steven Humphrey mass KNO 3 mass (NH 4 ) 2 Fe(SO 4 ) 2 . 6H 2 O mass KNO 3 crystals + filter paper mass KNO 3 crystallized % KNO 3 recovered (% of amt in Step A.3.) mass KNO 3 to be analyzed for purity (~0.1 g) mass KNO 3 crystals + filter paper mass KNO 3 crystallized % KNO 3 recovered (% of amt in Step A.3.) mass KNO 3 to be analyzed for purity (~0.4 g) EXPERIMENT 4: I. Fractional Crystallization of KNO 3 with (NH 4 ) 2 Fe(SO 4 ) 2 .6H 2 O Impurity II. The Solubility Curve of KNO 3 DATA, CALCULATIONS AND GRAPHS Part I: Fractional Crystallization of KNO 3 with (NH 4 ) 2 Fe(SO 4 ) 2 . 6H 2 O Impurity PURPOSE AND METHOD Part I We will use KNO3 and ferrous ammonium sulfate and make two mixtures by dissolving them into water. Then we will heat, cool and filter the solution to take away the impurities that we do not want. After filtration, we then can dry the mixture under a heat lamp, and take the mass of the remaining mixture. This task is performed two times. After the leftover mixture is dried and carefully take taken off from the filter paper, we will mix it with hydroxylamine, Phenathroline, and water. By transferring it into a cuvette and using the spectrophometer, we can calculate the absorbance. % Impurity = Mass of Ferrous Ammonium Sulfate / Total mass of sample mixture x 100% % KNO3 recovered = Mass KNO3 crystallized / Mass KNO3 x 100% From the leftovermass that we wanted to calculate in the first place, we can then calculate the % Impurity as well as the % KNO3 recovered....
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This note was uploaded on 10/27/2010 for the course CHEM 162 taught by Professor N. during the Summer '08 term at University of Washington.

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Chem 162 - Lab 4 - Grading: 60 pts Assigned Points 5 5 A....

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