30AL Soil Project

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CHEM 30AL : General Chemistry Laboratory II Soil Project Lab Report Unknown #12 Arnav Jhawar, Maggie Clark, Jessica Gonzalez TA: David Deluca Section: 1E

CHEM 30AL Soil Project Lab Report Group Responsibilities Arnav Jhawar : - Performed extraction, identification, and analysis of the inorganic molecules within the solution created from the unknown. - Conducted various tests, including Beer’s law, metal ion tests, and assisted in the analysis of the organic material on day 3 of the lab. - Assisted and contributed to the creation of the presentation slides, presented and contributed to the report. Maggie Clark : - In charge of the extraction, identification, and analysis of the organic molecules within the solution, created from the unknown. - Assisted in tests needed for organic analysis (TLC, mass spectroscopy, acid-base separation, UV spectrum, and melting point analysis). - Assisted and contributed to the creation of the presentation slides, presented and contributed to the report. Jessica Gonzalez : - In charge of the extraction, identification, and analysis of the organic molecules within the solution, created from the unknown. - Assisted in tests needed for organic analysis (TLC, mass spectroscopy, acid-base separation, UV spectrum, and melting point analysis). - Assisted and contributed to the creation of the presentation slides, presented and contributed to the report.

CHEM 30AL Soil Project Lab Report Abstract This project aimed to examine and understand the different substances present in a soil sample of unknown origin, labeled as sample 12. Through a series of experiments, we successfully identified and measured the amounts of both organic and inorganic compounds within the sample. The organic compounds found were naphthalene, a neutral substance, and m-nitroaniline, a basic substance. On the other hand, the inorganic compounds discovered were nickel (II) chloride (NiCl 2 ) and cobalt (II) sulfate (CoSO 4 ). To separate the organic and inorganic components, we utilized vacuum filtration after dissolving the sample in a mixture of hexane and ethyl acetate because one is polar and the other is non polar. We also employed an acid-base extraction to further separate the organic neutral and organic basic compounds from each other. For identification purposes, we utilized UV-vis, IR, and mass spectroscopy, and the compounds were purified through multiple liquid-liquid extractions. To assess the compound’s purity, we conducted TLC and melting point analyses. Similarly, for the inorganic compounds, we used UV-vis spectroscopy and specific tests to determine their presence. To obtain quantitative data, we performed colorimetry, a method that measures the intensity of color, based on which we analyzed Beer's Law. Calculations showed that the percentages by mass of the compounds in the sample were as follows: 1.4% naphthalene, 0.7% m-nitroaniline, 7.14% nickel chloride, and 4.48% cobalt sulfate.

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CHEM 30AL Soil Project Lab Report Design and Discussion of the experimental procedure Separating the Organic and Inorganic: 1. We weighed approximately 25 g of the unknown mixture and recorded the appearance and exact weight. 2. Dissolved the unknown mixture in a nonpolar organic solvent- which was a mixture of hexane and ethyl acetate. 3. We Gently stirred the solution with a glass stirring rod. 4. Poured the solution into a vacuum filtration setup. 5. Collected the filtrate and stored it in a separately labeled beaker “organic compound.” Green/yellow color. 6. Dissolved the residue in water and stored it in a separate beaker labeled “inorganic compound.” Red/brown color. Organic: 1. We ran an initial TLC test using a mixture of hexane and ethyl acetate at the bottom of the jar and found that the organic layer was most likely Naphthalene (neutral) and m- nitroaniline (basic). 2. Placed solution into a separatory funnel to perform liquid-liquid extraction with HCl to protonate the basic part of the organic layer because it was now neutral. 3. This made the m- nitroaniline move into the aqueous layer and make

CHEM 30AL Soil Project Lab Report the organic layer neutral. For only the 1st extraction we collected an aqueous layer in the beaker. 4. Repeated 5 times so the neutral organic layer was pure. For the other 4 extractions, aqueous was waste. 5. Added drying agent to neutral organic and air dried to get white precipitate. This is Naphthalene. 6. Added a base to aqueous to deprotonate the m- nitroaniline, add until ph>7, some precipitate forms, this was the m- nitroaniline. 7. Conducted a liquid-liquid extraction with the aqueous solution from #6 with ethyl acetate to dissolve the precipitate. Repeated three times. 8. took an ethyl acetate layer, added a drying agent, air dried, and got a yellow precipitate. This was m- nitroaniline. 9. Ran TLC, melting point, UV vis, IR spec, and mass spec on both the basic and neutral. Inorganic: DAY 1 1. The inorganic solution was not pure, so an initial liquid-liquid extraction with ethyl acetate was necessary to wash the solution. 3 washes were done to purify. There was still some organic in this aqueous solution that needed to be washed out. 2. Solution was ready to run metal tests.

CHEM 30AL Soil Project Lab Report 3. Culture Tube #1: A small amount of the inorganic solution was added. Ammonium hydroxide was added and nothing happened. Dimethyloxirane was added and the solution turned a bloody red. This indicates that we have Nickel. There was only one Nickel option that could be in the unknown, so we could conclude that we had NiCl 2 4. Culture Tube #2: A small amount of the inorganic solution was added. Potassium Nitrate added and nothing happens. The culture tube was placed into a heating bath and yellow precipitate formed. This indicates that we have Cobalt. We had to determine if we had CoCl 2 or CoSO 4 5. Culture Tube #3: A small amount of the inorganic solution was added. BaNO 3 was added and white precipitate formed. This indicates that there is SO 4 -2 6. Culture Tube #4: A small amount of the inorganic solution was added. AgNO 3 added and white precipitate forms. This indicates that there is SO 4 -2 and Cl - are present. By inductive reasoning, we determine that we must have CoSO 4 Inorganic: DAY 2 1. Added 4.017 g of NiCl 2 to 50 mL of water. This was the stock solution. 2. Made 3 standard solutions. Solution #1: 15 mL of stock in 25 mL volumetric ﬂask, diluted to the mark with water. Solution #2: 20 mL of

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CHEM 30AL Soil Project Lab Report Solution #1 in 25 mL volumetric ﬂask, diluted to the mark with water. Solution #3: 10 mL of Solution #2 in a 25 mL volumetric ﬂask, diluted to the mark with water. 3. Added 3.1920 g of CoSO 4 to 50 mL of water. This was the stock solution. 4. Made 3 standard solutions using the same instructions as above. 5. Measured absorbance of all the solutions above in addition to the inorganic solution from the unknown mixture.

CHEM 30AL Soil Project Lab Report (b) Our experimental scheme allowed for the separation and isolation of the organic and inorganic parts of our unknown solution though the first part of the procedure. The organic compounds were highly soluble in an organic solvent, so we used a mixture of ethyl acetate and hexane. We then rinsed our unknown and performed a vacuum filtration to separate the organic from the inorganic. The residue left on the filter paper was our inorganic and the solution in the beaker was the organic component. The inorganic is not soluble in our organic solvent, which allowed for an easy separation of the two. The inorganic is soluble in water. To determine what was in our organic solution, we first needed to determine if we had an acidic and neutral solution or basic and neutral solution. We ran a TLC test to find that we had a basic and neutral solution. We found on our initial TLC test that our solution was most likely made of Naphthalene (neutral) and m- nitroaniline (basic). After this, we performed a liquid-liquid extraction with an acid - HCl. This acid would protonate the base m- nitroaniline to make it neutral and move it into the aqueous layer. This would also neutralize the organic layer of just Naphthalene, allowing for the separation of the two. We repeated this extraction five times, only collecting the first aqueous layer and discarding the other four extracted aqueous layers. Since we had successfully separated the two organic

CHEM 30AL Soil Project Lab Report compounds, we needed to collect precipitates of them. For the neutral organic layer, we simply added a drying agent, air dried, and got a white precipitate - Naphthalene. To get a precipitate for the m- nitroaniline, we first needed to deprotonate the base by adding a base until the pH of the solution was greater than 7. A precipitate was formed and we added ethyl acetate to dissolve it. We then added a drying agent, air dried, and got a yellow precipitate - m- nitroaniline. With these two separated organic compounds, we could now run a TLC test, melting point, UV vis, IR spec, and mass spec to confirm what we had. When running the TLC, we used our sample and appear sample of what we thought were the compounds inside of our solution. One of the solutions that we used was Naphthalene, and our solution after running the TLC the circles aligned. We measured the distance that each circle moved and compared the difference, because the difference was fairly small, 0.2, we were able to conclude that one of the compounds we had was naphthalene. For the second TLC we did a similar procedure where we used pure m-nitroaniline and our sample to compare if we had it. We again measured the Rf value, which was 0.2. Therefore we were able to confirm that we had m-nitroaniline. The UV, Mass spec, and IR tests were mostly comparisons where we compared our samples results to these tests with literature results.

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CHEM 30AL Soil Project Lab Report For the identification of the inorganic component of the unknown, metal ion tests were performed. Before this could take place, we had to wash the solution three times with ethyl acetate to get rid of the organic compounds that were still present in the inorganic solution. This could have presented an inconsistency in our data if we did not completely remove all of the organic compounds. The first metal test that we did was for Nickel. We put a small amount of our inorganic sample into a culture tube then added ammonium hydroxide. We did not observe any change. When Dimethyloxirane was then added, the solution turned a bloody red. This was an indication that we had Nickel present in our solution. The only option for Nickel in the unknown was NiCl2. Next, we tested for the presence of Cobalt. Using the same set up, Potassium Nitrate was added and nothing was observed. When the culture tube was placed into a heating bath, a yellow precipitate was formed. This confirmed the presence of Cobalt. From here we needed to confirm whether this was CoCl2 or CoSO4. Using the same setup, BasNo3 was added and a white precipitate is observed. This indicates that SO4-2 is present. Our last test used the same setup and added AgNo3, a white precipitate is formed. This confirms that there is SO4-2 and Cl-. By process of elimination, we determine that the other metal is CoSO4. We then ran a UV Spec to confirm our results. We compared wavelengths and the curve shape to the literature that was given, confirming our results.

CHEM 30AL Soil Project Lab Report Next we created solutions to run to calculate their absorbance. This was done by creating a stock solution first and then diluting the solution in 3 steps to make 3 standard solutions. For Standard Solution 1, 10ml was taken from the stock and diluted in a 25 ml volumetric ﬂask. For Standard Solution 2, 15ml was taken from the Standard 1 and diluted in a 25 ml volumetric ﬂask. For Standard Solution 3, 20ml was taken from the Standard 2 and diluted in a 25 ml volumetric ﬂask. Absorbance measurements were taken for these and the clean unknown inorganic solution. The wavelengths set for Nickel Chloride and Cobalt Sulphate were 722nm and 550nm respectively with reference to the UV/Vis Spectras .

CHEM 30AL Soil Project Lab Report Results/Discussions for Qualitative Analysis (a) Organic: Melting Point Analysis Data Identified Compounds Start and End Temperatures ( ℃ ) Sample Melting Point Values ( ℃ ) Literature Melting Point Values ( ℃ ) m- nitroaniline 85 - 135 111.1 - 114.7 111 - 114 Naphthalene 50 - 100 78.1 - 81.1 79 - 82 When conducting the melting point analysis for naphthalene, we initially knew that the melting range for naphthalene was around 79 degrees Celsius to 82 degrees Celsius. Therefore, we set the melting point apparatus's start temperature to around 28 degrees below the initial melting point and set it to around 20 degrees above the ending melting point in order to see if our sample melted anywhere near that range. Our naphthalene sample melted at 78.1 degrees and stopped at 81.1 degrees celsius, which is within range and therefore allowed us to determine that our sample was naphthalene. Similarly, when testing for m-nitroaniline we set a range broader than the literature known melting range for m-nitroaniline, 111 degrees-114 degrees celsius. Our sample fell within the 111-114 degree Celsius range, and began melting at 111.1 degrees. Therefore allowing us to believe our sample contained m-nitroaniline.

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CHEM 30AL Soil Project Lab Report Both of the samples we tested melted within the literature melting ranges, with less than a 5 degree difference from the literature melting point of pure product. Therefore indicating that our samples were relatively pure. TLC Analysis Data m- nitroaniline Naphthalene Mobile Phase Ethyl Acetate Ethyl Acetate Solvent Front 5.0 cm 5.1 cm Distance traveled - Unknown #12 4.1 cm 3.5 cm Unknown R f 4.1 / 5.0 = 0.82 3.5 / 5.0 = 0.70 Distance traveled - Pure Compound 4.0 cm 3.6 cm Pure R f 4.0 / 5.0 = 0.80 3.6 / 5.0 = 0.72 Difference 0.82 - 0.80 = 0.02 0.72 - 0.70 = 0.02 The assumed m-nitroaniline sample only had a difference of 0.2 from the pure sample of m-nitroaniline and they both had a yellowish tint to them, so we were able to conclude the similarities and the presence of m-nitroaniline in our sample. The assumed naphthalene sample also only had a difference of 0.2 and was very close to the pure naphthalene sample.

CHEM 30AL Soil Project Lab Report (b) Inorganic Nickel Test Bloody Red Precipitate Cobalt Test Yellow Precipitate upon heating Silver Test White Precipitate Barium Test White Precipitate 1) Nickel Test DMG + NiCl 2 → Ni(DMG) 2 + 2H + + 2Cl - (2) Cobalt Test Co 3+ + 3KNO 2 → K 3 [Co(NO) 2 ] 6 (s) (3) Silver Test for Chloride anions AgNO 3 + NiCl 2 → AgCl (s) + Ni(NO 3 ) 2 (4) Barium Test for Sulphate anions CoSO 4 + Ba(NO) 3 → BaSO 4 + Co(NO 3 ) 2 Results for the Quantitative Analysis (% by Mass) Percent mass of Nickel Chloride % ???? = ???? ?? ?𝑖???? ?ℎ???𝑖?? ???? ?? ??𝑖? ?????? 𝑋 100% = 1.83 ????? 25.6 ????? 𝑋 100% = 7. 14 % Percent mass of Cobalt Sulphate % ???? = ???? ?? ?𝑖???? ?ℎ???𝑖?? ???? ?? ??𝑖? ?????? 𝑋 100%

CHEM 30AL Soil Project Lab Report = 1.15 ????? 25.634 ????? 𝑋 100% = 4. 48 % Percent mass of m-nitroaniline % ???? = 𝐺???? ?? ???????? 𝐺???? ?? ??????? #12 𝑋 100% = 0.199 ????? 25.634 ????? 𝑋 100% = 0. 7 % Percent mass of naphthalene % ???? = 𝐺???? ?? ???????? 𝐺???? ?? ??????? #12 𝑋 100% = 0.378 ????? 25.634 ????? 𝑋 100% = 1. 4 % Inorganic Components Nickel Chloride 4.017 grams of Nickel Chloride was dissolved in 50 ml of water no of moles = Mass of the compound dissolved Molecular weight of Nickel Chloride n = 4.01 grams 237.69 g/ moles n = 0.0169 mols

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CHEM 30AL Soil Project Lab Report Concentration of the solution C = nV C = 0.0169 moles 0.05 L C = 0.338 M Standard Solution #1 M1V1 = M2V2 (0.338 M)(10.00 ml) = (M2)(25.00 ml) 0.135 M = M2 Molarity of Standard Solution #1 = 0.135 moles/L Standard Solution #2 M1V1 = M2V2 (0.135 M)(15.00 ml) = (M2)(25.00 ml) 0.081 M = M2 Molarity of Standard Solution #2 = 0.081 moles/L Standard Solution #3 M1V1 = M2V2 (0.081 M)(20.00 ml) = (M2)(25.00 ml) 0.064 M = M2 Molarity of Standard Solution #3 = 0.064 moles/L

CHEM 30AL Soil Project Lab Report Equation: ? = ?? + ? ? = 3. 6281? + 0. 0093 Now, 𝐴 = ε?𝐶 and the slope is ε? Therefore, 0. 478 = 3. 6281(𝐶) + 0. 0093 0. 129 ? = 𝐶 Mass of Nickel Chloride 10 ml of the clean inorganic unknown solution was taken and diluted with 100 ml of DI water ? = 𝐶?

CHEM 30AL Soil Project Lab Report ? = (0. 129 ?????/?)(0. 11 ?) ? = 0. 0141 ???? ? = ???? ????????? ??𝑖?ℎ? ?? ?𝑖???? ?ℎ???𝑖?? 0. 0141 ???? = ? ? 129.60 ?/???? ? = 1. 83 ????? Cobalt Sulphate 4.984 grams of Cobalt Sulphate was dissolved in 50 ml of water ?? ?? ????? = ???? ?? ?ℎ? ???????? ?𝑖??????? ????????? ??𝑖?ℎ? ?? ?𝑖???? 𝐶ℎ???𝑖?? ? = 3.984 ????? 263.08 ?/ ???? ? = 0. 0151 ???? Concentration of the solution 𝐶 = ? ? 𝐶 = 0.0151 ???? 0.05 ? 𝐶 = 0. 31 ? Standard Solution #1 ? 1 ? 1 = ? 2 ? 2 (0. 31 ?)(10. 00 ??) = (? 2 )(25. 00 ??) 0. 12 ? = ? 2 Molarity of Standard Solution #1 = 0.12 moles/L Standard Solution #2

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CHEM 30AL Soil Project Lab Report ? 1 ? 1 = ? 2 ? 2 (0. 12 ?)(15. 00 ??) = (? 2 )(25. 00 ??) 0. 07 ? = ? 2 Molarity of Standard Solution #2 = 0.07 moles/L Standard Solution #3 ? 1 ? 1 = ? 2 ? 2 (0. 12 ?)(20. 00 ??) = (? 2 )(25. 00 ??) 0. 05 ? = ? 2 Molarity of Standard Solution #3 = 0.05 moles/L Equation:

CHEM 30AL Soil Project Lab Report ? = ?? + ? ? = 7. 2919? + 0. 057 Now, 𝐴 = ε?𝐶 and the slope is ε? Therefore, 0. 549 = 7. 2919(𝐶) + 0. 057 0. 067 ? = 𝐶 Mass of Nickel Chloride 10 ml of the clean inorganic unknown solution was taken and diluted with 100 ml of DI water ? = 𝐶? ? = (0. 067 ?????/?)(0. 11 ?) ? = 0. 0074 ???? ? = ???? ????????? ??𝑖?ℎ? ?? ?𝑖???? ?ℎ???𝑖?? 0. 0074 ???? = ? ? 154.99 ?/???? ? = 1. 15 ?????

CHEM 30AL Soil Project Lab Report Conclusion The compounds that we found in our soil sample were organic components naphthalene with a percent mass of 1.4%, m-nitroaniline with a percent mass of 0.7%, cobalt sulfate with a percent mass of 4.48%, and nickel with a percent mass of 7.14%. For our inorganic solution, the inorganic still contained some contamination of organic solution, which led to the need of multiple washes and the possibility of losing product in the process. The multiple washes and the use of different measurements of solute can add extra mL if not extracted correctly and can skew out results. Attachments - UV spec, IR spec, Mass Spec, TLC, literature IR, Literature UV spec, Literature mass spec. References https://sdbs.db.aist.go.jp/sdbs/cgi-bin/cre_index.cgi https://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi https://www.sigmaaldrich.com/US/en/sds/SIGALD/223387?sdslanguage=EN https://www.sigmaaldrich.com/US/en/sds/SIAL/544167 https://www.fishersci.com/store/msds?partNumber=AC174960050&productDescriptio n=NAPHTHALENE-D8+98%2B+ATOM+5GRNA&vendorId=VN00032119&countryCode= US&language=en https://www.fishersci.com/store/msds?partNumber=AC128361000&productDescriptio n=3-NITROANILINE%2C+99%2B%25+100GR3-N&vendorId=VN00032119&countryCode= US&language=en

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