Chem 1212k Lab Report

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Deborah Bell
April 17, 2012
Chemistry 1212K Lab Synthesis Report

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 did a gravity filtration. Added the filtrate to a mixture of 2 grams activated charcoal and 25 mL of aqueous ammonia concentrated. Add 6mL of 30% hydrogen peroxide 3-4 drops at a time and heated. Transfered to a beaker and add a boiling solution of 3 mL HBr and 135 mL water. Synthesis #3 yielded an orange colored powder.

2. Procedure for Analysis for percent Halide in a synthesized cobalt compound. Prepare AgNO3 first: Weigh out 1.7-1.8 grams of AgNO3 and dissolve it in 50 mL deionized water. Mix in 10 drops of concentrated HNO3. Crucibles were already at a constant weight. Weighed out.24-.25 gram samples. Added 125-150 mL of deionized water and 10 drops of HNO3. Add 25 mL of AgNO3 solution to each sample. Boil gently. Collect AgX in gooch crucible. Used suction flask to dry then they were cooled and weighed.

My results yielded 50.1 % Halide ± .12
% Yield Calculation:
Crucible 1 weight : 31.7986 g
31.7986-31.2969 = .5017 g
35.452143.327X .5017= .1240 .1240.2478= .5004 x 100=50.04% Halide
Crucible 2 weight : 31.2134 g
31.2134 – 30.7106 = .5028
35.452143.327 X .5028= .1243
.1243.2478= .5016 x 100=50.16 % Halide

3. Procedure for Preparation and Standardization of an HCl Solution : (HOCH2)3CNH2 + HCl → (HOCH2)CNH3 + Cl- In preparation calculated the mL of .3 HCl. Measure calculated volume and dilute with deionized water to get a total volume 500 mL in a beaker. Performed all standardizations in triplicate. Weighed THAM between .8000 and 1.1000 gram. Dissolve each sample in 90-100 mL deionized water and add 3.5 drops of indicator. Titrate solution with HCl solution. Watch for color change to greenish-blue color. My results yielded a yellowish green to green color. Average molarity .3056 M. Deviation ± 1 | Initial Vol| Final Vol| Total used| |

Trial 1| 20.48 mL| 41.49 mL| 21.10 ml| |
Trial 2| 7.32 mL| 41.05 mL| 33.73 mL| |
Trial 3| 7.49 mL| 32.21 mL| 28.72 mL| |

#1. 1.0193121.14 grmas per mole=8.4 x 10-3 moles
8.4 x 10-3 moles.02101 L= .3998 M
#2 .9364121.14 grams per mole =7.7 x 10-3 moles
7.7 x 10-3 moles.03373 L= .2282 M

#3 1.0159121.14 grams per mole=8.3 x 10-3 mole
8.3 x 10-3moles.02872 L= .2889 M

4. Procedure for Analysis of Percent NH3 using Standardized 0.3M HCl : NH3 + HCl → NH4 + Cl- This experiment is done in triplicate. Made 150 mL of 9M NaOH. Weigh out 3 samples of 2 grams of boric acid in 50 mL deionized water. Weighed synthesized CO sample .3500-.4000 grams on analytical. Set up the ammonia producing assembly. Add the synthesized Co to the flask and 100 mL deionized water. Add 50 mL NaOH and place stopper on quickly. Submerge other tip in the delivering glass. Turn on hot plate and continue heating for 15 minutes until contents boil. Keep plenty of ice around delivering flask so the liquid does not back up. Let cool add indicator , then titrate the trapped NH3 in boric acid solution with HCl. Calculate moles, grams, and % NH3. My results were average 24.37 % deviation ± 3.00

| Initial vol| Final vol| Total used| Deviation|
Trial 1| 13.01| 36.41| 17.13| .14|
Trial 2| 13.49|...
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