# 68th Ans Zinc

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Warm Up Questions: 1. Exercise 1: a. 2.56 ZnI2=x moles of ZnI2 b. 500 ml=0.500L c. The flask would be labeled as 0.0161 ZnI2/L Solution 2. Exercise 2: a. 0.43 g of ZnI2 B 5E-4 moles of ZnI2 c. 0.161M* x L=moles of ZnI2 in solution 84 mL for the first student 31 mL for the second student 3. Exercise 3: a. 2.56 g/500 mL (given) b. 0.00512 * 500 = 2.56 c. 0.00806 * 319.9= 2.56 d. 0.00806 * 319.9 = 2.56 500 mL =0.5 L e. 0.0161 * 500 / 2 =2.56 4. Exercise 4: a. 0.250M; 250 mL 0.25 L (0.25) (0.25) = 0.0625 moles ZnI2 b. Prepare the solution by dissolving 19.95 grams of Zinc Iodide with 250 mL of water. c. Prepare the solution by dissolving 38.90 grams of ZnI2 with 500 mL of water. d. 0.0125/0.25 = 0.05 L = 50 mL. This produces 0.0125 moles of ZnI2 5. Exercise 5: a. (0.125)(0.1) = 0.0125 moles of solute b. Pour 50 mL of the stock solution to get the number of moles needed. 6. Exercise 6: a. (0.02) (1) = x/ 372.24 x=7.4 grams of sodium EDTA that is weighted out. b. The molarity would be 0.02M. 7. Exercise 7: a. (0.050) (0.1) = 0.0083 moles b. Pour 8.3 mL of the stock solution to get the amount needed. c. Measure out 8.3 mL in a graduated cylinder 8. Exercise 8: a. 41.8 mL are used b. 0.00079 moles EDTA4- c. 0.00079 moles ZnI2 d. 0.0517 grams of ZnI2 are in the sample e. 0.0517/0.237= 21.8% f. Error Is 6.34% Lab Report: Part 1: In this lab we used the following supplies: * Zinc Iodide * Na2H2EDTA(s) * Calmagite indicator solution * pH 10 buffer solution * 6M Acetic Acid * Unknown Zinc Compound The main purpose for this part of the lab was to determine the amount of zinc ion in a sample of ZnI2 by titration. The two types of zinc: * Zinc iodide made by zinc and iodine * Commercially purchased zinc iodide (the