Fractional Crystallization of KNO3 with (NH4)2Fe(SO4)2·6H2O Impurity Part II. Determining the Solubilty Curve of KNO3

Fractional Crystallization of KNO3 with (NH4)2Fe(SO4)2·6H2O Impurity Part II. Determining the Solubilty Curve of KNO3. Laboratory Waste Evaluation Laboratory waste is considered anything generated during an experiment that is disposed of down the sewer draingarbage, collected in a container for disposal by the UW Environmental Health & Safety department, or released inenvironment. Based on the written lab procedure and your actions during the lab, list the identity and approximateor volume) of waste that you generated while performing this experiment. - 10 g KNO3 - 1g NH43FeSO4 Page 2 of 28 - 10 g KNO3 - 1g NH43FeSO4 - filter paper -weighing paper - ice and tap water - papertowels - sodium bicarbonate and pH strips Page 3 of 28 NAME: QUIZ SECTION: DATA, CALCULATIONS, AND GRAPHS Part I. Fractional Crystallization of KNO 3 with (NH4)2Fe(SO4)2·6H2O Impurity A. Starting Components (Fract. Crystallization #0) Step 3: Mixture before first crystallization mass KNO3 mass (NH4 )2Fe(SO4 )2 . 6H2O Total mass of the sample mixture % Impurity (i.e., % Fe compound in the mixture)* *(This is your % impurity for Fract. Crystallization # 0) Fract. Crystallization #1 Step 7: mass of dry filter paper + watch glass Step 10: mass of KNO3 crystals + filter paper + watch glass mass of KNO3 crystallized % KNO3 recovered (% of KNO3 in Step A.3.) Step 11: mass of KNO3 crystals to be analyzed for purity in Part I.C B. Fract. Crystallization # 2 (Re-crystallization) Step 5: mass of dry filter paper + watch glass Step 7: mass of KNO3 crystals + filter paper + watch glass mass of KNO3 crystallized % KNO3 recovered (% of KNO3 in Step A.3.) Step 8: mass of KNO3 crystals to be analyzed for purity in Part I.C Page 4 of 28 Page 5 of 28 NAME: QUIZ SECTION: C. Analysis to Determine % Impurity First Crystallization Step 3: Absorbance of the Fe(phen)3 2+ complex at 510 nm What is your absorbance after dilution? (if applicable) Multiply your absorbance by the dilution factor (if applicable) Molar Absorptivity of ferroin, e Calculate the molarity of Fe2+ from the absorbance (pathlength = 1 cm) Volume of ferroin complex solution prepared in Steps C.1. and C.2. Calculate the moles of Fe2+ (moles of Fe2+= moles of (NH4 )2Fe(SO4 )2 ·6H2O) Calculate the molar mass (NH4 )2Fe(SO4 )2 ·6H2O Calculate grams of (NH4 )2Fe(SO4 )2 ·6H2O in the crystals Mass KNO3 crystals analyzed for purity (from Step A.11.) (this cell will autofill) Does the absorbance exceed the desired range (0 to 2.0 A)? ______no______ If so, what dilution factor did you use in order to get the absorbance in the desired range? ______N/A_______ Type your calculation for molarity of Fe2+ (1 mol ferroin = 1 mol Fe2+) A=E*I*c 1.526= 1.25 x 10^4 1/M*cm * 1 cm * C C = 1.221 x 10^-4 M Type your calculation for moles of Fe2+ 1.221 x 10 ^-4 M= x moles/ 0.01 L 1.221 x 10 ^-4 M * 0.01 L = 1.221 X 10^-6 moles