G short report

5. After stopping the vacuum, the waste filtrates were thrown out and the apparatus was then reassembled and turned on. 6. Another several mL of HNO 3 were poured over the precipitates in the Buchner funnels. Once the acid had passed through, the vacuum was stopped and unassembled again. 7. Several mL of the washing was poured into two separate test tubes, making sure to not fill them completely, and 3 drops of HCl were pipetted into the tubes to test for completion of wash test. a. If any cloudiness was visible in the tubes, steps 1-7 in the washing procedure were repeated until the washings remained clear. 8. The contents of the test tubes were discarded into the sink and the tubes were cleansed with distilled water. Excess wash from the filter glasses were also discarded in the sink. 9. Once the vacuum was reassembled and turned on, the precipitates were covered with acetone. Once the liquid had passed through, this process was repeated 2 more times. 10. Once the precipitates were dry, the vacuum was turned off and the apparatus was disassembled. The acetone glasses were then disposed of in their respective container. Drying and massing of precipitates: 1. Over a piece of paper towel, the filter papers were carefully removed from their funnels using a micro spatula and transferred into their respective 50.00 mL beakers, making sure all solids went into the beaker. 2. Each 50.00 mL beaker was placed into an oven at 86.0 °C for 13 minutes. 3. After the samples had cooled for 4 minutes, each beaker with its precipitate and filter paper was massed using the analytical balance. 4. Once values were measured, the filter papers and precipitates were disposed of and all instruments were thoroughly cleaned using distilled water. Data and Observations: 1. Once the AgNO 3 was added to the solutions, they became a cloudy, opaque white. a. Grey precipitate formed in the solutions instantly. 2. If the samples failed the precipitation test for completion, grey, clumpy matter would form in the solution. 3. Several grams of precipitate filtered through the vacuum while the washing test was being conducted. 4. A small amount of precipitate was left stuck to the 250.00 mL beakers and the Buchner funnels, unable to be rinsed or scraped off into the final massed samples. 5. The temperature of the oven quickly rose from 80.0 °C to 86.0 °C within 3 minutes of placing the 50.00 mL beakers inside. The temperature remained relatively consistent throughout the rest of the drying process. • Table 1: Initial and final description of the physical changes of each sample Sample Initial Physical Description (salt) Final Physical Description (precipitate)

Sample calculation using data for sample number 1: 0.1M AgNO 3 ¿ ( ( ( 0.1306 g× 55% 35.5 g mol ) 0.1 M ) × 1000 L ) + 5.00 mL = 25.2338 mL ≈ 25.23 mL ∴ Approximately 25.23 mL AgNO 3 is required for sample 1 and 20.73 mL is required for sample 2. %uncertainty = ( Salt MassU ncertainty Sample Mass 1 ) × 100 = ( 0.0002 g 0.1306 g ) × 100 ≈ ± 0.15 % ∴ The percent uncertainty of the volume of AgNO 3 required is approximately ± 0.15 % for sample 1 and ± 0.20 % for sample 2. Calculation of the percent chloride in each sample: The moles of chloride in each sample were calculated using the following equation: Using values gathered from sample 1: Moles Cl 1 ¯ = ( Mass of Precipitate 1 Molar Mass of AgCl ) = ( 0.1716 g 143.32 g mol ) ≈ 0.001197 mol ∴ There are 0.001197 mol Cl - in sample 1 and 0.001811 mol Cl - in sample 2. %uncertainty = ( Precipitate MassUncertainty Precipitate Mass 1 ) × 100 = ( 0.0002 g 0.1716 g ) × 100 ≈ ± 0.23 % In moles: uncertainty = ( % Uncertainty 100% ) × Moles Cl 1 ¯ = ( 0.23% 100% ) × 0.001197 mol ≈ ± 0.000003 mol ∴ The percent uncertainty of the volume of AgNO 3 required is approximately ± 0.23% or ± 0.000003 mol for sample 1 and ± 0.15 % or ± 0.000003 mol.

it could terminate this effect of the silver “coat” during photodecomposition, creating more chlorine gas. Leading to a third cause, while heating the solutions to trigger the formation of crystalline structures, the precipitate test could have been incomplete, which would have triggered additional substance loss through the filter as they would not have been big enough to be held back. This was observed in the filtration procedure. As well, during precipitate transfer from the 250.00 mL beaker and the Buchner funnel, small but noticeable amounts of precipitate were left behind, unable to be removed or scraped into the target instrument. This would have also contributed to the lower chloride percentage. Conclusion: To conclude, the percent of chloride in the samples collected of salt 377 were determined to be approximately 32.54 ± 0.39 % for sample 1 and 63.35 ± 0.35 % for sample 2, with a final average percentage of approximately 47.95 ± 0.37%. The results presented a relative error of about 11.39 % lower than the given value of 54.11 %, which could have been attributed mainly to sources of error in the precipitation and/or washing tests leading to the escape of chlorine gas. Additionally, the relative spread of the chloride percentages was calculated to be about 642.45 ppt, exhibiting an insufficiency in accuracy with the data collected.