Comprehensive Analysis and Identification of a Synthesized Cobalt Amine Bromide Compound: Overcoming Challenges and Ensuring Precision

In addition to the specific procedures outlined above, it is crucial to delve into further aspects of the experimental process. The preparation and standardization of the HCl Titrant deserve special attention, as they play a pivotal role in the accurate determination of the quantities involved. The meticulous preparation of the titrant ensures its reliability and effectiveness in the subsequent titration processes.

The synthesis process involved not only the combination of cobalt, ammonia, and bromine but also meticulous distillation techniques to purify the resulting compound.

The distillation step was crucial in separating and isolating the desired product from impurities, contributing to the accuracy of the subsequent analyses.

Moreover, the filtration process employed in the experiment demands consideration. The efficiency of the filtration step directly impacts the purity of the synthesized compound, influencing the accuracy of the overall analysis. Proper filtration ensures the removal of any undesired particles or residues that might interfere with the precise determination of the compound's composition.

In conclusion, the comprehensive experimental procedures discussed above, including the analysis of the percentage of Halide, NH3, and Co, along with the preparation and standardization of the HCl Titrant, distillation, and filtration, collectively contribute to the reliability and accuracy of the results.

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The consistent and meticulous execution of each step in Synthesis V leads to the confident identification of the synthesized compound as [Co(NH3)5Br]Br2, reinforcing the significance of the conducted experiments in advancing our understanding of the molecular composition of the synthesized compounds.

The central challenge addressed in this series of laboratory experiments revolves around determining the molecular formula of a compound synthesized through specific procedures.

The focus of this discussion centers on Synthesis V, which involves the preparation of a Cobalt Amine Bromide product. Following the synthesis, the compound undergoes a sequence of titration processes and distillation to isolate the gas contained within. As outlined in the laboratory manual, the primary objective is to acquaint oneself with the procedures necessary for identifying an essentially unknown compound. Furthermore, this discussion will delve into potential errors in experimentation and deviations from expected outcomes.

The synthesis procedure involves the preparation of a Cobalt Amine Bromide product, a critical step in the subsequent analyses. The synthesis process encompasses the meticulous combination of cobalt, amine, and bromide, creating the target compound. This step serves as the foundation for the comprehensive analysis to follow.

Following synthesis, the compound undergoes titration processes and distillation. Titration is a crucial analytical technique employed to determine the concentration of specific components within the synthesized compound. It involves the controlled addition of a titrant to the sample, with careful monitoring until a reaction endpoint is reached. Distillation, on the other hand, is a purification process that separates components based on their boiling points. In this context, it is employed to isolate the gas present in the compound, contributing to the overall identification process.

It is essential to acknowledge the potential for errors in experimentation. The recognition of possible pitfalls or inaccuracies in the procedures is crucial for a thorough understanding of the experimental outcomes. Deviations from expected results will be explored, providing insight into the reliability and precision of the conducted experiments.

In conclusion, Synthesis V and its associated procedures offer a unique opportunity to explore the synthesis and analysis of a Cobalt Amine Bromide compound. The focus on titration, distillation, and error analysis enhances the understanding of the experimental process, contributing to a more comprehensive grasp of molecular identification.

To initiate the experiment, precisely four grams of CoCO3 are to be accurately measured and added incrementally to a 250mL beaker containing 15mL of 9M (48%) hydrobromic acid. The addition process is meticulous, ensuring that each portion is added gradually. Upon the cessation of fizzing, indicating the completion of the reaction, 10mL of water is gently introduced into the mixture. Subsequently, the stirred mixture undergoes gravity filtration for separation. The filtrate obtained is then combined with 7g of NH4Br, which has been dissolved in 35mL of ammonia (aq) in a separate 250mL beaker. The resulting mixture is transferred into an ice bath, aiming to cool it to a temperature of 10 degrees Celsius or below.

While in the ice bath, a cautious addition of 7mL of 30% H2O2 follows, with careful intervals of 4-5 drops at a time and stirring for 20-30 seconds between each addition. Once the desired temperature is achieved, and all of the H2O2 has been added, the mixture undergoes heating on a hot plate until only 2/3 of the original volume remains. Continuous stirring is employed to expedite the boiling process. Upon reaching the desired volume, the mixture is withdrawn from the hot plate and allowed to cool to room temperature.

During the cooling phase, a 4.5M solution of HBr is prepared by combining 25mL of 48% HBr with 25mL of water, cooled to room temperature. When both mixtures attain room temperature, the 50mL of HBr solution is cautiously introduced into the original mixture. Subsequently, the entire mixture undergoes another heating phase at approximately 60-70 degrees Celsius for 45-60 minutes until 2/3 of the original volume is once again achieved.

Upon completion, the mixture undergoes cooling in an ice bath to reach a temperature of 10 degrees Celsius or less, facilitating the collection of crystals through suction filtration. After draining off all liquids, the crystals undergo a washing process with 10mL of ethyl alcohol and 10mL of acetone, delivered in two 5mL portions each. Once the filtration process concludes, signified by the crystals appearing rather dry, they are left to air dry for a week and subsequently weighed, resulting in 9.0173g of formed crystals.

This comprehensive procedure ensures the careful execution of each step in the synthesis process, contributing to the successful formation and characterization of the crystals.

Preparation of AgNO3 Precipitating Reagent Solution involved the precise measurement of 1.7267g of AgNO3 (s), which was subsequently dissolved in 50mL of deionized water. Approximately 10 drops of concentrated HNO3 were incorporated into the solution to enhance its efficacy as a precipitating reagent. The average weights of crucibles were determined to be 31.3284g and 30.6258g.

Two distinct cobalt samples, each weighing approximately 0.24-0.25g, were meticulously transferred to separate beakers. To each sample, 125-150mL of deionized water and 10 drops of HNO3 were added. Subsequently, 25mL of the previously prepared AgNO3 solution was introduced to each sample. The samples underwent a gentle boiling process for 45 minutes, followed by cooling to room temperature. The resulting precipitates from each sample were meticulously collected into separate crucibles, which had been pre-dried and weighed.

The crucibles, now containing the precipitates, were placed on a suction filtration flask for further filtering. To wet the contents in the crucible, 5mL of ethyl alcohol was applied. Once the alcohol had successfully filtered through, 5-6mL of acetone was poured onto the precipitate. Following approximately 2-3 minutes of filtration, the crucibles were transferred to a beaker and subjected to drying in the oven for a duration of 30 minutes. Afterward, the crucibles were allowed to cool for 25 minutes before undergoing weighing. This drying and weighing process was repeated until the difference in weight was within the acceptable range of 0.0005g.

The acquired data and calculations pertaining to the % Halide Analysis are presented in Table 1. The mass of each Co-sample, the mass of the precipitate, and the calculated % halide in each Co-sample were tabulated. The average % Halide in Co-sample was determined to be 59.28%, with a minimal deviation of 0.27%.

This meticulous experimental procedure, coupled with precise measurements and careful analysis, ensures the reliability and accuracy of the results obtained during the % Halide Analysis.

Calculations 1: % Halide Analysis
Sample Calculation: 0.3419gAgBr/187.77gAgBr/mol * 79.909Brg/mol = 0.1455gBr
Br and AgBr 1:1 ratio, 0.1455gBr/0.2448gCo-sample = 59.44% Halide
Average: (59.44+59.12)/2 = 59.28% Halide
Deviation: (59.44-59.28)/59.28 * 100 = 0.27% & same for second sample
(0.27+0.27)/2 = 0.27%

Preparation and Calibration of HCl Solution

While this particular experiment may not directly yield insights into the Co-Compound, its significance lies in the fact that the HCl solution produced here plays a crucial role in the subsequent titration with the compound, aiding in the determination of the % NH3.

For the preparation of the approximately 0.3M HCl solution, a meticulous process is followed. A precise measurement of 12.5mL of HCl is taken, and it is subsequently diluted with deionized water, reaching a total volume of 500mL. The mixture is stirred for 2-3 minutes to ensure proper homogenization before being transferred to a screw-cap bottle for storage.

Moving on to the standardization of the HCl solution, a quantity ranging from 0.8000g to 1.1000g of THAM is precisely weighed out and placed into a 250mL Erlenmeyer flask. The THAM is then dissolved in 90-100mL of deionized water, creating a solution for titration. To facilitate the titration process, 3-5 drops of brom-cresol-green indicator are added to the flask. The contents of the flask are then titrated with the prepared HCl solution until an optimal green color is achieved, indicating the completion of the reaction.

This step-by-step procedure not only ensures the accurate preparation of the HCl solution but also guarantees its reliability through the standardization process. The HCl solution, once prepared and standardized, becomes a precise and effective titrant for subsequent analyses, contributing valuable information to the overall understanding of the Co-Compound composition. The attention to detail in the preparation and standardization stages reinforces the credibility of the experimental results.

In summary, while this experiment may seem ancillary to the primary focus on the Co-Compound, its role in providing a standardized HCl solution for titration is indispensable, bridging the gap between experimental components and enhancing the accuracy of the overall analysis.

Data and calculations for overall Molarity of HCl solution are as follows, with the chemical equation:
(HOCH2)3CNH2 + HCl -> (HOCH2)3CNH3+ + Cl-
Data Table 2: Molarity of HCl Solution
Mass of THAM Vol. HCl used Molarity of HCl
0.8290g 23.00mL 0.2957M
0.8228g 22.85mL 0.2976M
0.8016g 22.30mL 0.2960M
Average Molarity: 0.2964M HCl with 0.2587% deviation
Calculations 2: Molarity of HCl Solution
Sample Calculation: 0.8290gTHAM/121.14THAMg/mol = 0.0068molHCl (HCl & THAM 1:1 ratio)
0.0068molHCl/0.02300LHCl = 0.2957M HCl
Average Molarity: (0.2957+0.2976+0.2960)/3 = 0.2964M
Deviation: Sample for one value: (0.2957-0.2964)/0.2964 * 100 = 0.2362
Standard Deviation -> (0.2362+0.4049+0.1350)/3 = 0.2587%

Analysis of % NH3 Using Standardized HCl

The methodology for analyzing the % NH3 in the Co-Compound closely resembles the earlier steps involved in standardizing the HCl solution, but with an additional crucial step preceding the titration process. Prior to titrating to determine the % NH3, it is imperative to distill the NH3 gas from the compound.

The initial step involves the preparation of 150mL of 9M NaOH, achieved through a 1:1 dilution of 50% NaOH, which is subsequently cooled to room temperature. Three 250mL Erlenmeyer flasks are then readied, each containing 2.0g of Boric Acid dissolved in 50mL of DI water. Ensuring complete dissolution of boric acid in each flask is a crucial preliminary step. Three distinct samples of the Co-Compound are accurately weighed out.

Setting up the apparatus for ammonia production involves the elevation of a hot plate on a tripod, with an adjacent ice bath containing the boric acid mixture. A clean Erlenmeyer flask is placed on the hot plate, and the weighed Co-Compound is added to the flask. After rinsing the entire sample into the flask with DI water and reaching a total volume of 50mL, gentle stirring is initiated on the hot plate. Subsequently, 50mL of NaOH is swiftly added to the flask with the Co-Compound, followed by securing a tight rubber seal on the flask. The glass tube is immediately placed into the flask containing the boric acid.

Once a steady boil is achieved, the boiling process continues for an additional 20-35 minutes. At the conclusion of the boiling, both flasks are left in place to cool, with the rubber stopper removed after 4-5 minutes. The delivering tube is slightly raised to rinse off any residue using DI water. The boric acid flask, now containing trapped NH3, undergoes the addition of 3-5 drops of brom-cresol-green indicator and is subsequently titrated with the standardized HCl solution.

This elaborate procedure ensures the successful distillation of NH3 gas from the Co-Compound, providing a crucial step in the subsequent titration process. The inclusion of the brom-cresol-green indicator adds precision to the titration, enabling accurate determination of the % NH3 in the Co-Compound.

Data and calculations are as follows:
(during distillation) NH3 + H3BO3 -> NH4+ + H2BO3-
(during titration) H2BO3- + HCl -> H3BO3 + Cl-
(Overall Equation) NH3 + HCl -> NH4+ + Cl-
Data Table 3: % NH3 Analysis
Mass of Co-Compound Vol. HCl in Titration % NH3 in Co-Compound
0.3568g 14.90mL 21%
0.3577g 15.10mL 21.2%
0.3573g 15.00mL 21.3%
Average % NH3: 21.2% with 0.47% deviation
Calculation 3: % NH3 Analysis
Sample Calculation: 0.01490L * 0.2964M HCl * 17.024NH3 g/mol = 0.075g NH3
% NH3 = 0.075g NH3/0.3568g Co-Com * 100 = 21%
Average -> (21+21.2+21.3)/3 = 21.2%
Deviation -> (21-21.2)/21.2 * 100 = 0.94%
(0.94+0+0.47)/3 = 0.47%
Preparation and Standardization of 0.1M Na2S2O3 (Sodium Thiosulfate):

The objective of this experiment aligns with the earlier HCl solution experiment, focusing on the preparation of a titrant. However, in this case, the aim is to analyze the quantity of Cobalt in the compound.

The preparation involves the meticulous creation of 500mL of 0.1M (aq) Na2S2O3. This is achieved by dissolving 12.4g of S2O3 2- in water, with the remainder filled by deionized water. To preserve the solution, 0.3g of Na2CO3 is dissolved in Na2S2O3. The standardization process is conducted in triplicate to ensure accuracy.

To standardize the solution, 0.1000-0.1200g of KIO3 is accurately weighed and placed into a clean Erlenmeyer flask. Subsequently, 70-80mL of deionized water is added to dissolve the KIO3. Following this, 3.0g of KI is weighed and introduced to the KIO3 mixture. The addition of 3mL of 6M HCl under a hood triggers dissolution, creating a brownish-red color. The solution is swiftly titrated with the prepared Sodium Thiosulfate until the first indication of colorless.

The chemical equation governing this titration is expressed as follows:
IO3−​+6H++6S2​O32−​→3S4​O62−​+I−+3H2​O
This comprehensive procedure ensures the accurate preparation and standardization of the Na2S2O3 solution, establishing it as a reliable titrant for the subsequent analysis of Cobalt in the compound. The repetition of the standardization process enhances the precision and reliability of the results, contributing to the overall success of the experiment.
Data Table 4: Standardization of Na2S2O3
Mass of KIO3 Vol. of Na2S2O3 Molarity of Na2S2O3
0.1030g 27.60mL 0.1051M
0.1024g 27.30mL 0.1062M
0.1021g 27.20mL 0.1066M
Average Molarity of Na2S2O3: 0.1060M with 0.53% deviation
Calculation 4: Standardization of Na2S2O3
KIO3 + 6HCl + 6Na2S2O3 -> 3Na2S4O6 + KI + 3H2O + 6NaCl
Sample calculation: 0.1030g KIO3/214KIO3 g/mol * 6mole Na2S2O3 = 0.0029molNa2S2O3
Molarity -> 0.0029molNa2S2O3/0.0276L = 0.1051M Na2S2O3
Average -> (0.1051+0.1062+0.1066)/3 = 0.1060M
Deviation -> 0.1051-0.1060 = 0.0009
(0.0009+0.0002+0.0006)/0.1060 * 100 = 0.53%

Analysis of % Co3+ Using Standardized 0.1M Sodium Thiosulfate

In this phase of the experiment, the focus shifts to the analysis of % Co3+ in the Co-Compound, employing the standardized 0.1M Sodium Thiosulfate solution as the titrant.

Commencing the procedure involves the precise weighing of three distinct samples, each ranging from 0.5000g to 0.7000g, of the Co-Compound. These samples are then individually placed into separate, pristine Erlenmeyer flasks, with a minimal amount of deionized water used to ensure the transfer of the entire compound into the flask. Subsequently, 35mL of deionized water is added to each flask, along with 10mL of 50% NaOH. The mixtures undergo heating and gentle boiling under a hood for a duration of 20 minutes, followed by cooling to room temperature in an ice bath. It's noteworthy that the subsequent steps must be conducted for each sample individually.

The process continues with the weighing of 2.0g of KI, which is then added to the cooled contents in the flask. The contents are swirled for 4-5 minutes to ensure thorough mixing. Under the hood, 40-50mL of 6M HCl is added to the mixture incrementally in small 3-4mL portions, with intermittent swirling between each addition. The addition of HCl continues until a red-brown color is achieved. At this point, 5mL of Sodium Thiosulfate and 5mL of Starch indicator are swiftly introduced. The titration process with Sodium Thiosulfate ensues, continuing until the dark color initially disappears.

This meticulous procedure ensures the accurate analysis of % Co3+ in the Co-Compound. The step-by-step approach, along with the utilization of standardized Sodium Thiosulfate as the titrant, enhances the reliability and precision of the results. The individual treatment of each sample ensures a thorough and accurate evaluation of the % Co3+ content, contributing to the overall success of the experiment.

Data and Calculations are as follows:
2Co(NH3)4Cl3 + 2S2O32- -> 2Co+2 + S4O6 2- + 8NH3 + 6Cl-
Data Table 5: % Co Analysis
Mass of Co-Sample Vol. of Na2S2O3 % Co
0.5018g 12.80mL 15.9%
0.5072g 13.00mL 16.01%
0.5047g 12.85mL 15.9%
Average % Co: 15.94% with a 0.31% deviation
Calculation 5: % Co Analysis
Sample calculation: 0.01280L Na2S2O3 * 0.1060M Na2S2O3 * 58.93Co g/mol = 0.0800g Co
% Co = (0.0800g Co/0.5018g Co) * 100 = 15.9%
Average -> (15.9+16.01+15.9)/3 = 15.94%
Deviation -> 15.9-15.94 = 0.04
Standard Deviation = (0.04+0.07+0.04)/3 = 0.05 -> 0.05/15.94 *100 = 0.31%
Additionally, it is imperative to highlight the role of meticulousness in laboratory procedures, especially during titration experiments. The accurate preparation of titrants is a fundamental aspect, and any deviation in the process could lead to significant alterations in the chemical equations and subsequent calculations. Therefore, the importance of precision and attention to detail cannot be overstated.

Furthermore, the collaborative nature of laboratory work also played a crucial role in the successful execution of the experiments. Effective communication among team members helped address confusion regarding instructions, ensuring that procedures were followed consistently. This collaborative effort underscores the importance of clear communication in a laboratory setting, minimizing the potential for misinterpretation and errors.

Despite the challenges encountered, the results of the experiments provide valuable insights into the composition of the synthesized compound. The calculated percentages of each substance in the sample contribute to a comprehensive understanding of the molecular structure. The acknowledgment of potential limitations and uncertainties serves as a foundation for future improvements in experimental design and execution.

In conclusion, while the experiments faced challenges related to time constraints and potential human errors, the overall success in identifying the Co-Compound formula attests to the effectiveness of the experimental approach. The commitment to accuracy, collaboration, and continual improvement in laboratory practices collectively contribute to the advancement of chemical analysis techniques and our understanding of synthesized compounds.

Results and Conclusion

Upon completion of the series of experiments aimed at determining the percentage of each component in the synthesized Co-Compound sample, the obtained data is as follows: an average of 59.28% for the halide (Bromine), with a deviation of 0.27%; an average of 21.2% for Ammonia, with a deviation of 0.47%; and an average of 15.94% for Cobalt, with a deviation of 0.31%. These values were meticulously gathered with the utmost precision.

Subsequent to the data collection, a comparative analysis was performed using a reference chart provided in the lab manual, leading to two potential conclusions. The Co-Compound could be identified as either [Co(NH3)6]Br3 or [Co(NH3)5Br]Br2. Although the data points for both formulas were in close proximity, the experimental data for [Co(NH3)5Br]Br2 exhibited a higher degree of consistency across the three analyzed components. While the % Halide for [Co(NH3)6]Br3 was closer to the experimental data, the % Ammonia and % Cobalt for [Co(NH3)5Br]Br2 demonstrated a more accurate alignment.

The preference for [Co(NH3)5Br]Br2 as the more accurate identification is justified by considering the comprehensive nature of the titration processes involved in obtaining the % Ammonia and % Cobalt data. Titration provides more precise information about a compound, revealing crucial characteristics such as the pKa and reactivity of the sample. Notably, titration was employed to determine the presence of the challenging-to-identify substance, ammonia gas, which adds a layer of reliability to the overall conclusion. In contrast, the % Halide Analysis was conducted at an earlier stage, potentially introducing variations.

In summary, the identification of [Co(NH3)5Br]Br2 as the Co-Compound is grounded in the majority of data sets aligning closely with experimental findings. While the % Halide for [Co(NH3)6]Br3 was closer, the preference for [Co(NH3)5Br]Br2 is justified by the stronger consistency in the data for % Ammonia and % Cobalt. Therefore, the conclusion drawn from Synthesis V is that the synthesized compound is indeed [Co(NH3)5Br]Br2.