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. Today’s Lab Lecture (3/16): Your questions… Introduction to Unknowns Midterm 2:10 – 4pm in your lab Rules: Cell phones off and in your pack. Do bring a calculator, but not a "computer". No sharing... Do not leave the room during the exam. No extra note paper; use back of pages if necessary. Please no questions during exam (unless you discover a serious mistake). You can write: "if I understand the question this way..." No "late" exams... A midterm not taken earns the grade "F".

3. Introduction to Unknowns For instructions and experimental details see Chapter 10, pp.618 - …., in your Mayo text For a list of Unknowns and their derivatives see our ERES files Sample “Unknown” problems are in our ERES Exam Folder

4. 1. What is typical of the molecules of compounds that have an odor? 2. Which organic compounds tend to have a "pleasant" odor? And which tend to have a "bad" odor"? 3. What characteristic features do you find in the molecule structure of organic compounds that have a color? Unknowns Preliminary Tests pp. 618 - 626

5. 1.What does the melting point tell you? 2.What does the boiling point tell you? Preliminary Tests Unknowns

6. What information do you obtain from the ignition test? Compare with known compound! How do you test for unsaturation? Compare with known compound! What information is obtained with the Beilstein test (p.626)? Compare with known compound! Preliminary Tests (We do not perform tests on pp. 622 – 625)

7. What type of information do you get if your unknown 1. is soluble in water? 2. is soluble in NaOH and in NaHCO 3 ? (equation) 3. is soluble in NaOH only, not in NaHCO 3 ? (equation) 4. is soluble in dilute HCl solution? (equation) 5. is soluble only in conc H 2 SO 4 ? 6. is not soluble in any of the above solvents? Solubility Tests (pp. 626 – 627) Do these carefully!

8. 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, you will prepare two Derivatives (related solid compounds with a defined, listed mp.)

9. Next time: “Unknowns”: - Aldehydes and Ketones - Alcohols and Phenols (Unknown #1!)