sadaf 68th adn zinc final;

sadaf 68th adn zinc final; - Sadaf Ayaz Professor Edmund...

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Sadaf Ayaz Professor Edmund Tam Lab Partners: Natalia and Gaby 03/20/2016 68 th and Zinc Raw Data: Description of all substances used Substances Description Zinc Iodide(Commercial) yellow-orange powder Na2H2 EDTA (s) White powder, sugar-like particles Calmagite indicator solution Purple, wine-reddish color, liquid pH 10 Buffer clear, water-like, strong odor 6 M Acetic Acid Water-like, clear “Unknown” Zinc Compound white powder, sugar-like Synthesized ZnI2 gray, light brown powder Description of Color Change at endpoint Our solution, originally pink because of the Calmagite Indicator solution, first turned dark purple with each drop of the EDTA solution, then slowly became a lighter purple to a bluish color. At times it was hard to determine if the solution had finally turned blue or was still light purple, so we added a few more drops of the EDTA solution until we were sure the color was in fact blue, indicating it had reached the endpoint. Tabulated Masses TRIAL 1 KNOWN SUBSTANCES Substance Measurement Na 2 H 2 EDTA in solution 3.65 g Distilled water in solution About 250 mL Concentration of EDTA 4- 0.392 M (mol/L) 3.65 g / 372.24 g/mol = 0.0098mol 0.0098 mol / 0.250 L = 0.0392 M
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TRIAL 2 KNOWN SUBSTANCES Substance Measurement Na 2 H 2 EDTA in Stock EDTA Solution 14.6 g H 2 O in Stock EDTA Solution 1000 mL Concentration of EDTA 4- 0.392 M 14.6g / 372.24 g/mol = 0.0392 mol 0.0392 mol / 1 L =0.0392 M TRIAL 3 KNOWN SUBSTANCES TRIAL 1 UNKNOWN SUBSTANCE Commercial ZnI 2 0.25 g Initial reading of EDTA buret of commercial buret of commercial Total volume of titrated Concentration of EDTA 4- used 0.392 M (.0228L)(.0392M) = 0.00089 (.00089)(65.38) = .058 g Zn (.058/.25)*100 = 23.2% (.02235L)(.0392M) = 0.00088 Commercial ZnI 2 0.25 g Initial reading of EDTA 4- in buret of commercial 50.0 mL Final reading of EDTA 4- in buret of commercial 28.1 mL Total volume of EDTA 4- titrated 21.9mL Concentration of EDTA 4- used 0.392 M (.0219L)(.0392M) = 0.00086 (.00086)(65.38) = .056 g Zn (.056/.25)*100 = 22.45% Synthesis ZnI 2 0.25 g Initial reading of EDTA 4- in buret of synthesis 50.0 mL Final reading of EDTA 4- in buret of synthesis 23.6 mL Total volume of EDTA 4- titrated 26.4mL Concentration of EDTA 4- used 0.392 M (.0264L)(.0392M) = 0.00103 (.00103)(65.38) = .0677 g Zn (.0677/.25)*100 = 27.06% Substance Measurement Na 2 H 2 EDTA in Stock EDTA Solution 14.6 g H 2 O in Stock EDTA Solution 1000 mL Concentration of EDTA 4- 0.392 M 14.6g / 372.24 g/mol = 0.0392 mol 0.0392 mol / 1 L =0.0392 M Commercial ZnI 2 0.25 g Initial reading of EDTA 4- in buret of commercial 50.0 mL Final reading of EDTA 4- in buret of commercial 26.4 mL Total volume of EDTA 4- titrated 23.6 mL (.0236L)(.0392M) = 0.00093 (.00093)(65.38) = .0605 g Zn (.0605/.25)*100 = 24.2% Synthesis ZnI 2 0.25 g Initial reading of EDTA 4- in buret of synthesis 50.0 mL Final reading of EDTA 4- in buret of synthesis 23.9 mL Total volume of EDTA 4- titrated 26.1 mL (.0261L)(.0392M) = 0.00102 (.00102)(65.38) = .0667 g Zn (.0667/.25)*100 = 26.68%
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Grams of Unknown .16 grams Concentration of EDTA4- .0392 M Total Volume of EDTA4- titrated 28.9 mL .0289 L Percentages (0.0392M)(0.0211L)= 0.000827mol (0.000827mol)(65.38g/mol)= 0.054g (0.054g)/(0.16g) x 100 = 33.79% TRIAL 2 UNKNOWN SUBSTANCE Trial 2 Grams of Unknown .16 grams Concentration of EDTA4- .0392 M Total Volume of EDTA4- titrated 30.8 mL .0308 L Percentages ( 0.0392M)(0.0192L) = 0.000752mol of Zn (0.000752mol)(65.38g/mol) = 0.0492g (0.0492g)/(0.16g) x 100 = 30.75% Equation: EDTA 4- (aq) + Zn 2 (aq) [Zn [EDTA ]] 2- Focus Questions: 1. What is the percent Zinc of Zinc Iodide as determined by a Titrimetric Analysis?
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