Peter Chau Exp #4 CHE 3610L Mar 6, 2023 Nitrate and Sulfate Ion Absorption Band Predictions Based on Group Theory Objective10 Using IR spectrometry and group theory, the number of absorption bands will be predicted for nitrate and sulfate ions. Background5,10 Infrared spectrometry is an analytical technique that utilizes infrared light to identify chemical substances and functional groups in the test chemical. The data processed through the spectrometer is produced as a spectrum that graphs absorbance vs frequency. The spectrum allows us to utilize the knowledge of different absorbance rates to identify the ones that are present in the product. For example, bands with the frequencies 1500 – 1800, are identified as C=O bond being present. IR spectroscopy is also a good technique to determine the structure of compounds because depending on how the chemical is structured, it will transmit a different vibrational frequency, which is dependent on the molecule’s symmetry. There are many ways to conduct IR spectroscopy. The samples can be prepared and analyzed in many forms: as a powder, liquid, gas, solution, mull, or pellet. Every form has its reason for being used. Another note about symmetry, it can be mathematically applied to obtain information about a substance’s physical properties using a method called Group Theory. The method utilizes “groups” which are a set of symmetric elements, to rationalize and understand bonding features of the molecule. Using the following element analysis: C=72.7% P=10.3% Cu=7.1% H=5.1% O=3.6% S=1.7% It was deduced that the empirical formula of the final compound is C113P6Cu2H95O4S. Chemical Reactions10 (a) P(C6H5)3 + C2H3N = (b) CuO + C2H3N + H2SO4 = (c) + CH3CH2OCH2CH3 = Procedure10 1. Prepare KBr pellets and/or Nujol Mull samples of AgNO3 and Pb(NO3)2 2. Dissolve 5.6 g of triphenylphosphine in 30 mL of acetonitrile and then warm the solution in a steam bath 3. While steaming, suspend 0.5 g of copper (I) oxide into 10 mL of acetonitrile in a test tube 4. Add sulfuric acid drop wise until the red color has discharged and most of the solid has dissolved 5. Combine the two mixtures, using gravity to filter 6. Evaporate the filtrate to ~20 mL in a steam bath under a fume hood 7. Cool to room temperature 8. Add diethyl ether slowly while stirring (~50 mL) 9. Filter the product and dry it 10. Use the IR spectrometer to produce a spectrum 11. Place a little copper (I) oxide into a tube of 2M sulfuric acid and heat it up 12. Compare the 2M sulfuric acid reaction with the acetonitrile reaction in Step 3 All waste must be discarded into the proper chemical waste containers and equipment be thoroughly washed. Figures7 Chemical List1,2,3,4,6,8,9,11,12 Silver (I) nitrate, 169.87 g.mol, AgNO3, Odorless, colorless, solid, MP: 212 C, BP: 440 C Not flammable, oxidizer May be corrosive to metal, severe burns to skin, highly toxic to aquatic life Lead (II) nitrate, 331.21 g/mol, Pb(NO3)2, Odorless, white, solid, MP: 470 C, BP: 500+ C, water soluble Not flammable, oxidizer Harmful if swallowed or inhaled, serious eye damage, damage to organs if prolonged exposure, very toxic to aquatic life Potassium bromide, 119.0 g/mol, KBr, Odorless, colorless, crystalline, MP: 734 C, BP: 1435 C Water soluble Causes serious eye damage Mineral Oil, 452.363 g/mol, C16H10N2Na2O7S2, Odorless, colorless, liquid, MP: -15 C, BP: 218-800 C N/A Not a hazardous substance Triphenylphosphine, 262.29 g.mol, P(C6H5)3, Odorless, white, crystalline, MP: 79-81 C, BP: 377 C, water soluble Not flammable Harmful if swallowed, serious eye damage Acetonitrile, 41.05 g/mol, C2H3N, Ether-like smell, colorless, liquid, MP: -48 C, BP: 81-81 C, water soluble Flammable, combustible Highly flammable, harmful if swallowed, serious eye irritation Copper(I) oxide, 143.09 g/mol, CuO, Odorless, dark red, powder, MP: 1230 C N/A Harmful if swallowed or inhaled, serious eye damage, very toxic to aquatic life Sulfuric acid, 98.08 g/mol, H2SO4, Odorless, colorless, liquid, MP: 10.31 C, BP: 290 C, soluble N/A Corrosive to metals, sever burn to skin and eye Diethyl ether, 74.12 g/mol, CH3CH2OCH2CH3, Sweet, ether-like smell, colorless, liquid, MP: -116 C, BP: -34.6 C, soluble Flammable, combustible Extremely flammable, harmful if swallowed, may cause dizziness References 1. Acetonitrile; MSDS No. 271004 [online]; NOVEMBER 15, 2022. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/271004 (accessed 03/04/23) 2. Copper(I) Oxidel; MSDS No. 566284 [online]; SEPTEMBER 06, 2022. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/566284 (accessed 03/04/23) 3. Diethyl Ether; MSDS No. 296082 [online]; DECEMBER 08, 2022. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/296082 (accessed 03/04/23) 4. Lead(II) Nitrate; MSDS No. 228621 [online]; FEBRUARY 07, 2023. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/228621 (accessed 03/04/23) 5. Libretexts. Group theory and its application to chemistry https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook _Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Group_Theory/G roup_Theory_and_its_Application_to_Chemistry (accessed Mar 5, 2023). 6. Mineral oil; MSDS No. 330779 [online]; JULY 22, 2022. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/330779 (accessed 03/04/23) 7. NicoletTM iS20 FTIR Spectrometer https://www.thermofisher.com/order/catalog/product/IQLAADGAAGFAHDMBKG (accessed 04/03/23). 8. Potassium Bromide; MSDS No. 221864 [online]; MARCH 29, 2021. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/221864 (accessed 03/04/23) 9. Silver Nitrate; MSDS No. 204390 [online]; MARCH 30, 2021. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/204390 (accessed 03/04/23) 10. Spanopoulos, I. 3610L Intermediate Inorganic Chemistry lab manual Spring 2023, 2023. (accessed 03/04/23) 11. Sulfuric Acid; MSDS No. 339704 [online]; FEBRUARY 07, 2023. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/339704 (accessed 03/04/23) 12. Triphenylphosphine; MSDS No. t84409 [online]; OCTOBER 27, 2021. Available from Sigma Aldrich. https://www.sigmaaldrich.com/US/en/sds/usp/t84409 (accessed 03/04/23)
