Juliana Park Mayumi Tamada CHEM 111B LAB/ M-F 1-4PM 15 August 2012 Spectroscopy Lab Introduction In this lab, the molar absorptivity of the complex FeLn2+ will be determined by using the absorbance of the complex and its concentration. The absorbance will be found by using a spectrophotometer. For the next part of the lab, the formula of the complex will be determined by also using the volume of ligand and the absorbance again. Experimental There are two different parts to the experiement. In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water.
Then you put the remaining liquid (neutral component mixture) through the suction ﬁltration funnel to isolate the crystals. After 10-15 minutes, the crystals will be dry and you can weigh them and ﬁnd their melting point. How is the neutral component of your 3-compound mixture isolated from the ﬁnal methylene chloride solution? 16 of 22 4/16/12 9:15 PM StudyBlue Flashcard Printing of Lab Final 2211L UGA http://www.studyblue.com/servlet/printFlashcardDeck?deckId=... Name the four active ingredients that we will be testing for in the TLC of Analgesics lab: Ibuprophen Caffeine Acetaminophen Acetylsalicylic acid What solvent system will you be using to dissolve the common analgesics (power) in preparation for TLC spotting? Methylene chloride: ethanol (1:1 solution) What solvent system will you be using to "develop" your TLC plates in the TLC of Analgesics lab?
Calculate the Normality of the vinegar using the previously given equation. Na = (Nb)(Volumeb) (Volumea) C. Calculate the mass of the acetic acid in grams using the previously given equation. Massa = (Na)(GMWa) D. Calculate the percentage of acetic acid using the previously given equation. % Acid = Massa(g/L) x 100 1000g/L Discussion and Conclusion: Questions: LabPaq question guidelines: Answer questions A and G in the lab manual. Skip questions B, C, D, E and F in the lab manual, and answer these instead: A.
4. Calculate the molarity of the commercial bleach (not diluted) using your answer from step 3 and the M¬1V1 = M2V2 equation. (Use volume of concentrated bleach and total volume of dilute bleach) 5. Assume that the density of the commercial bleach is 1.08g/mL. Calculate the percent by mass of NaClO in the commercial bleach.
Investigating the Chemical Composition of Alka Selzter Problem: How much sodium bicarbonate is in a tablet of Alka Seltzer? Purpose: To discover the amount of sodium bicarbonate, in grams, in a one tablet of Alka Seltzer. Materials: one Alka Seltzer tablet 50 mL of vinegar post-it note Triple beam balance beaker Procedure: 1) Put the post-it on the triple beam balance and zero the balance. 2) Measure the masses of the alka-seltzer tablet, and the beaker + vinegar. Record them.
After a series of washes to remove any impurities, the compound was dried and decanted, cholesterol was synthesized. Melting points were obtained from commercial cholesterol, dibromocholesterol, and synthesized cholesterol using the Fisher-John Melting Point Apparatus. A TLC plate was completed, spotting commercial cholesterol, dibromocholesterol, and synthesized cholesterol. The silica gel was used as the stationary phase and the ethyl acetate: hexane (30:70) was used as the mobile phase. The silver nitrate test was conducted to test for the functional group of 2°and 3° alkyl halides as positive and negative controls were used.
The known nutrient solutions were used to create a base-line for protein, starch, and sugars. As listed in Table 1; protein (5g/L), Starch (0.2g/L), and sugar (20g/L) were separated in to 9 different test tubes at 2ml a piece, 3 per nutrient solution and tested for colormetry with the 400ug of the three reagents Lugol’s, Biuret, and Benedicts. Further steps were taken with the nutrients treated with Benedict’s reagent and they were heated in a water bath until they reached a constant 65 degrees C for 7 minutes and let cool to see color change. Distinguishing Organic Molecules in Unknown Dietary Supplements The same reagents used in setting the baseline were used to test the unknowns for nutrient content. Each of the 3 unknowns was distributed by dispensing 2ml of sample solution in to three test tubes.
Assume the left beaker contains 4 mM NaCl, 9 mM glucose, and 10 mM albumin. The right beaker contains 10 mM NaCl, 10 mM glucose, and 40 mM albumin. Furthermore, the dialysis membrane is permeable to all substances except albumin. State whether the substance will move (a) to the right beaker, (b) to the left beaker, or (c) not move. Glucose _____ Albumin _____ Water _____ NaCl _____ (3 points) 10.
Using another 125-mL flask, 60-mL of 0.3622 M potassium hydroxide in ethanol was deposited. Both flasks were clamped in a temperature-controlled bath regulated at 50.0˚C. The solutions were then set in the temperature bath for ten minutes to equilibrate. An empty 250-mL Erlenmeyer flask was also clamped in the same water bath. In another flask 50-mL of ice water was deposited with three-drop phenolphthalein.
Results Sheet, Experiment 13 Brand of Vinegar used:________________ Acetic Acid % from bottle label_____________ | Initial NaOH Reading(estimate to 0.1 mL) | Final NaOH Reading(estimate to 0.1 mL) | Volume NaOH used(Final – Initial) | Trial 1 | 9.5 | 1.3 | 8.2 | Trial 2 | 9.6 | 1.4 | 8.2 | Trial 3 | 9.7 | 1.4 | 8.3 | Average Volume of NaOH used | 8.2 | Calculations: Normality of the acetic acid: .82 Mass of acetic acid: 49.2 % acetic acid (divide the grams, above, by the volume you used to get g/L): 4.92 Answer questions A-G in the lab manual: A. What is the average % acetic acid in your vinegar sample? Standard vinegar is 5% acetic acid. How does your result compare with the standard? The average was 4.92 which is pretty close comparably to the standard.