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Mass of zinc = 1.050 g.     Calculate the number of moles of zinc in the 250 mL flask. please show working out. thank you

Mass of zinc = 1.050 g.     Calculate the number of moles of zinc in the 250 mL flask. please show working out. thank you

Chemistry
Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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Mass of zinc = 1.050 g.

 

 

  1. Calculate the number of moles of zinc in the 250 mL flask. please show working out. thank you 
PROCEDURE: 1. In a weighing bottle, weigh out accurately on the analytical balance 0.9 - 1.1 g of the zinc metal provided. 2. Transfer the metal carefully to a 50 ml conical flask and in the fume hood, carefully add ~4 ml of concentrated HCl into the flask to dissolve the metal 3. Cool the solution and add concentrated NaOH drop-wise until a permanent faint white precipitate forms. 4. Add 5 M HCl drop-wise to neutralize the solution until the zinc hydroxide (Zn(OH)2) precipitate just dissolves. Add a further 5 drops more of the acid to acidify the solution. Transfer the solution carefully to a 250 ml volumetric flask and make up to the mark with distilled water. Stopper the flask firmly and shake it to ensure a homogeneous solution. Using a buretta deliver exactly 20.00 ml of the standard zinc solution into a clean 5. 6. 250 ml conical flask. Add 70 ml of distilled water and 10 ml of the buffer solution (pH = 10). Then add four (4) drops of the indicator solution 7. Repeat step (6) a further 3 times so that you have a total of four conical flasks of solution for consecutive titrations. 8. Titrate with the EDTA solution until the end-point is reached (WINE-RED to PURE BLUE). 9. Repeat the titration until three (3) concordant results are obtained.
Transcribed Image Text:PROCEDURE: 1. In a weighing bottle, weigh out accurately on the analytical balance 0.9 - 1.1 g of the zinc metal provided. 2. Transfer the metal carefully to a 50 ml conical flask and in the fume hood, carefully add ~4 ml of concentrated HCl into the flask to dissolve the metal 3. Cool the solution and add concentrated NaOH drop-wise until a permanent faint white precipitate forms. 4. Add 5 M HCl drop-wise to neutralize the solution until the zinc hydroxide (Zn(OH)2) precipitate just dissolves. Add a further 5 drops more of the acid to acidify the solution. Transfer the solution carefully to a 250 ml volumetric flask and make up to the mark with distilled water. Stopper the flask firmly and shake it to ensure a homogeneous solution. Using a buretta deliver exactly 20.00 ml of the standard zinc solution into a clean 5. 6. 250 ml conical flask. Add 70 ml of distilled water and 10 ml of the buffer solution (pH = 10). Then add four (4) drops of the indicator solution 7. Repeat step (6) a further 3 times so that you have a total of four conical flasks of solution for consecutive titrations. 8. Titrate with the EDTA solution until the end-point is reached (WINE-RED to PURE BLUE). 9. Repeat the titration until three (3) concordant results are obtained.
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