Deborah Bell
April 17, 2012
Chemistry 1212K Lab Synthesis Report
Introduction In this Chemistry Lab the main objective is to perform accurate chemical analysis for the quantity of elements and compounds in a sample. There will be a compound made then synthesized. The methods used were acid-base titrations, redox titrations, gravity filtration, and distillation. General conclusions included
Procedures
Weight of Crucibles
1. The first experiment is Preparation of a Cobalt Amine Bromide Product ; Synthesis #3 was used to create the compound. Added 5 grams of cobalt carbonate to 20 mL of hrdrobromic acid in a beaker. Noticied a slight color change to dark purple. Solution frothed after it settled I mixed in 15mL water and…show more content… Heat the mixture strong for about 20 minutes but not vigorous. Add enough water to make the volue 50 mL. Cool the flask to room temperature. Weigh 2 grams of KJ and add it to the flask. Then add 40-50 mL of HCl increments. The solution change to a redish browm acidic color. Cooled solution and titrate using standardized sodium thiosulfate.
My results yielded were 22.51% ± .86
Trial 1:
.1261 M S2O3 x .01923 L = .002424 mol Co
.002424 mol Co x 58.93 MW Co = .1428 grams Co
.1428 g Co.5017 g= .2847 x 100=28.47 % | Initial vol | Final vol | Vol used | Trial 1 | 18.23 | 37.46 | 19.23 | Trial 2 | 12.24 | 31.34 | 19.10 | Trial 3 | 19.64 | 39.14 | 19.50 |
7. Procedure for Analysis H2O2 in commercial 3% Solution H2O2 + 2 S2O2 + 2 H → S4O6 + 2 H2O
Retrieve 3 clean flasks and put 50 mL deionized water and 1.5 grams KI in each. Then add about 20 drops of 12M HCl to each and swirl to mix. Make sure everything is dissolved. Pipet exactly 1 mL of fresh opened peroxide into the solution. Titrate the reddish-brown mixture with Na2S2O3 until a yellow color remains. Immediately add 3.5 drops mL of starch indicator. Solution changes to a very dark color. Titrate again until the dark color disappear.
My results yielded were an average Percent H2O2 of 9.1% ± 1.2 .
Trial 1 : .279 x 19.19 x 342000= .0910 x 100=9.10 %
Trial 2 :
.279 x 19.40 x 342000 = .090 x 100 = 9.0 %
Trial 3:
.279 x 19.24 x 34= 2000 = .0913 x 100 = 9.13& | Initial vol |
