After the recitation, we will meet back in the laboratory. Organic Chemistry Lab 315 Fall, 2016 For Tues., Sept. 20, we will meet in room 312 Planetary Hall at 1:00 p.m. After the recitation, we will meet back in the laboratory.

DUE DATES Today No report due. Since this is a continuation lab, and we are not starting an experiment today, there is no written pre-lab. Remember to print out and bring with you the Spectroscopy PowerPoint from the class webpage. At end of lab -- copy of laboratory notebook pages for today's work – finish crystallization experiment (details later).

DUE DATES Next Week At the beginning of class, “Crystallization Report” (Instructions posted separately on the class webpage later this week.) Spectroscopy Problem Set problems Part I (found linked to 315 Experiment List page).

Graded Materials Simply following instructions will get you far in this class. Pay attention to them – they are not random and they are meant to be followed. Many of you did not put your name on the Quiz Answer Sheet in the blank provided. You will need to find your quiz, write your name on it and return it to me, by the end of class. Read the assignment and watch the video – quiz questions come directly from these.

Graded Materials You can look at your Crystallization notebook copy, but you cannot keep it. Please return it to me today. Purpose – again merely copying the lab manual with no elaboration (“a solid/three solvents”). Chemical Property Table – chemicals clearly used and b.pts. were important. Structure of fluorene was explicitly asked for in the Manual. Neglecting to weigh the storage container when the Manual explicitly said to. Some of you need to record more carefully the procedure and observations – too sparse.

Graded Materials Melting Pt. and Refractive Index Report When asked to record an Unknown number on a vial, record the entire number. Many of you only recorded the “9” from “Set #9” and ignored the 3-digit unknown number. A common mistake was in citing physical properties of knowns and identified unknowns. Citing physical properties was the reading assignment for the first week. The “Lab Reports” page with instructions for the report you were to turn in made special mention of it and provided a link. The Manual was very explicit about approved sources (CRC Handbook, Merck, and DOC). No others are allowed. All compounds have unique identifying codes in the sources, and these must be given as part of the reference, as explained and illustrated in the Manual.

Graded Materials Melting Pt. and Refractive Index Report Too many of you ignored the temperature when recording the refractive index. The temperature is important and must be recorded. The Manual and textbook illustrated the symbols. nD23.5 = 1.4087 The temperature is recorded for the original measurement as well as for the temperature-corrected measurement that is compared to the literature value The Report Form was explicit in telling you to calculate your temperature correction on that page – how could that be ignored? Some of you ignored the instructions for writing the report that were on the website. Again, please read instructions!

In Lab Today Finish crystallization experiment Weigh container + dry product (and container if not done last week) to get final dry mass of fluorene and calculate a % recovery. Put product in vial (see next slide). Determine m.pt. of recrystallized product and do a mixed m.pt. of product + pure fluorene. Be sure to comment on your results in your notebook. Affix label (see Manual/Pavia for information to include on label). Store in class drawer. Turn in product with Report next week. Get products ready TODAY – there will not be time next week for you to fix a label, etc.

Notes Transferring a solid to a vial If funnel bottom is not available, make a funnel from a small piece of paper.

Percent Recovery whole = all of that with which you began part = that which has been isolated Remember, you cannot achieve (nor expect to) 100% recovery. Some of the original substance was soluble in the solvent at 0 deg., and some of the original material in the vial was an impurity. Review significant figures for use in Recrystallization Report calculation.

Next Week Next week you will be given a liquid unknown to identify by: Boiling point (new technique of simple distillation) Refractive Index (you will need to review this – many of you temperature-corrected in the wrong direction). IR spectrum

Clean up Traver, Gregory Relitz, Samuel