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Volunteers needed To help doing chemistry activities (“Plant smells and molecules”)

Join us as a volunteer to help with chemistry activities for young children and their families at the ACS Earth Day event in Martinez on April 17 and the ACS Boy Scout Jamboree in Pleasanton on April 18. Email us if interested!

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Volunteers needed To help doing chemistry activities (“Plant smells and molecules”)

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  1. Volunteers needed • To help doing chemistry activities (“Plant smells and molecules”) • with youngsters and their families • Saturday, April17 (~ 10-2) ACS Earth Day event, Martinez • Sunday, April 18 (~ 9-1) ACS at Boy Scout Jamboree, Pleasanton • Please email me if you can help. • Thank you!

  2. Introduction to Unknowns(You have about two weeks to complete each unknown)For instructions and experimental details see Chapter 10, pp.618 - …., in your Mayo textFor a list of Unknowns and their derivatives see our ERES filesSample “Unknown” problems are in our ERES Exam Folder

  3. UnknownsPreliminary Tests pp. 618 - 626 • What is typical of the molecules of compounds that have an odor? • Which organic compounds tend to have a "pleasant" odor? And which tend to have a "bad" odor"? • What characteristic features do you find in the molecule structure of organic compounds that have a color?

  4. Preliminary Tests • Mp. for solids What needs to be remembered for a good mp. measurement? • Which compounds tend to have high mp.s? low mp.s? • Bp. for liquids Which compounds tend to have high bp.s? low bp.s? • Refractive index for liquidsa physical characteristic, defines a compound • Ignition test information? • Test for unsaturation • Beilstein test for halogen (p.626)

  5. Solubility Tests (pp. 626 – 627) What type of information do you get if your unknown 1. is soluble in water? 2. is soluble in NaOH and in NaHCO3? 3. is soluble in NaOH only, not in NaHCO3? 4. is soluble in dilute HCl solution? 5. is soluble only in conc H2SO4? 6. is not soluble in any of the above solvents?

  6. After the Solubility tests you will do Classification tests(specific for a certain functional group) Once you have a reasonably good idea what your unknown could be (check ERES file), you will prepare two Derivatives(related solid compounds with a defined, listed mp.)

  7. Unknown #1can be:Aldehyde KetoneAlcoholor Phenol

  8. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Aldehydes and Ketonesfunctional groups? • Typical properties…. • Mp., bp., solubility…

  9. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Classification Tests for Aldehydes and Ketones 2,4-dinitrophenylhydrazone • also a good derivative! • What are desirable properties of a derivative? • What is the purpose of preparing a derivative? • →Prepare two good derivatives of each unknown. Recrystallize from ethanol/water.

  10. Aldehydes and Ketones To distinguish between aldehydes and ketones: • Preliminary tests • Solubility • Classification tests • Derivatives • Spectra • Tollens Test: • Jones (chromic acid): check reagent! Test is also positive for …..? • Schiff reagent: check reagent! • Always do with a known compound to compare!

  11. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Aldehydes and Ketones DerivativesImines:2,4-dinitrophenylhydrazoneoximesemicarbazone

  12. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Alcohols and PhenolsSolubility distinction? Solubility: Alcohols: “neutral”; Phenols: very weak acids, pKa around 10, except nitrophenols! • Classification tests: • Jones (also positive with 1o, 2o alcohols, amines…!) • Lucas test for 3o alcohols, 2o alcohols (slow): • Phenols only: Complexation with Fe 3+

  13. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Alcohol and Phenol Derivatives • with 3,5-dinitrobenzoyl chloride • urethanes Similarly: Naphthyl urethanes

  14. Anthocyanin Colors:Phenolic plant pigments responsible for blue, purple, pink colors in plants. Can complex with metal ions in soil, are pH sensitive

  15. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Aldehydes and Ketones IR: H-NMR:

  16. Preliminary tests • Solubility • Classification tests • Derivatives • Spectra Alcohols IR: H-NMR: Exchange with D2O

  17. Phenols Sample Compound: Phenol IR H-NMR

  18. Next time (after Spring Break) : Unknown 1 (cont.) Unknown #2: Carboxylic Acid, Ester, Amide, Amine (Cl, Br, nitro)

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