for the week beginning March 19, 2001

CHM 2200C Experiments for the Week Beginning March 19, 2001

Supplemental Information

[NOTE: The TAs are authorized to dismiss from the laboratory any student, who arrives after the starting time for the lab meeting and/or who has not prepared the lab notebook appropriately. A student so dismissed from a laboratory meeting will receive a grade of zero for each missed experiment. If you miss a laboratory meeting for what you think is a valid reason, provide a copy of documentation to Dr. Hilinski; if the excuse is deemed a valid one, a time to make up the missed experiment may be arranged.]

I. Experiment 54 - Basicity of Amines (pages 267-270)

You will do this experiment with 5 M aqueous anmonia, with triethylamine, and also with aniline. You will use pH paper instead of litmus paper, and you will record the pH reading based on the color of the spot.

Before coming to laboratory, prepare your lab notebook by writing equations for the reaction of each of the above compounds with 3 M hydrochloric acid, and for what happens when an excess of 3 M aqueous NaOH is added to the products of the first reaction (see pages 482-486 of the lecture textbook).

Carry out the procedures on pages 267-268 of the lab manual, and record your observations regarding odor, solubility, and pH in your lab notebook. Answer the questions on pages 269-270 in your lab notebook as you record your observations.

Based on the observed pH reading of the solution on the pH test strip (procedure step 2), does the compound give an appreciable concentration of OH^- ions in water? If yes, then write an equation for the equilibrium reaction giving rise to the OH^- ions.

II. Experiment 55 - Hydrolysis of an Amide (pages 271-274)

You will carry out the hydrolysis of benzamide in two ways, with NaOH and with hydrochloric acid.

Before coming to laboratory, prepare your lab notebook ahead of time by writing equations for the hydrolysis of benzamide with both of the reagents. Enter questions 1 - 4 from page 273, and answer them for both reactions (see pages 491-492 of the lecture textbook).

Carry out the alkaline hydrolysis and acidic hydrolysis reactions at the same time in separate test tubes. For the alkaline hydrolysis, follow the procedure on page 271 of the lab manual; then do the addition of 1 mL of concentrated HCl as called for in step 3, page 274. For the acidic hydrolysis, use the same procedure but substitute 3 mL of concentrated hydrochloric acid for the sodium hydroxide solution (Caution: do NOT attempt to smell this reaction mixture!). After allowing the acidic reaction mixture to cool, transfer about 1 mL of it to a clean test tube and add about 5 mL of 3 M NaOH solution until it becomes basic (test it with pH paper), then observe the odor.