Chemistry Web Site, Ron Sobczak http

At the start of each lab, we will have a discussion and introduction to the lab (including a quiz).

Late Lab reports: For lab reports that are up to one lab period late, the overall grade for that experiment will automatically be reduced by one letter grade(10 points). Lab reports will not be accepted if they are more than one lab period late.

Students are responsible for doing their own work on lab reports, including prelab, lab procedure, post lab and questions. Only the data collected in lab is to be shared. Copying anything except the shared data within a group is a violation of the honor code.

8/30 Experiment – Physical Methods of Separation and Purification, Experiment 1, QUIZ on Safety & Exp 1, bring Goggles and lab notebook, Theory: Define the different types of separation (decantation, filtration, extraction, distillation, sublimation) and explain what they are good for. MSDS: water, ethanol (ethyl alcohol), sugar (sucrose), iodine, potassium iodide, methylene chloride (dichloromethane). All methlyene chloride must go into the halogentated organic waste bottle. In your conclusion, discuss how effective each separation technique was. If a technique was not as effective as it should have been, explain why. Which technique do you feel is most powerful as a means of separation? Explain why Questions: Answer the questions that appear in the description of the techniques (Q-1 to Q-4). Answer the two questions at the end of the lab.

Question 1 in Experiment 1: heterogeneous vs. homogeneous (chapter 1 in Hill & Kolb) A homogeneous mixture has a uniform composition throughout (it does not matter where you take the sample from). A heterogeneous mixture has more than one phase and does not have a uniform composition throughout. Examples from lab: (1) ethanol and methylene blue (distillation) was a homogeneous mixture (solution). (2) Iodine and sodium iodide dissolved in water was a homogeneous mixture (solution). (3) But when you add methylene chloride with water, you have 2 phases and therefore it is a heterogeneous mixture. (4) sand and water is not uniform in composition and therefore is a heterogeneous mixture.

Note: In the extraction of iodine, the methylene chloride solution (purple after extraction) should go in the halogenated waste. The water layer should not go in that bottle, only the methylene chloride fraction (you will lose points if you do not dispose of the methylene chloride waste correctly).

9/13 Experiment - Identification of Unknown, Experiment 2, QUIZ on Exp 1 (separation techniques, attractive forces) & 2 (hazards), Theory: define physical properties (mp, bp, density, solubility, polar and nonpolar solvents, attractive forces) MSDS: water, ethanol or ethyl alcohol, toluene (C₇H₈). All toluene must go into the nonhalogentated organic waste bottle (you will lose points if you do not dispose of the toluene waste correctly). In your conclusion, summarize the data that justifies the identification of your unknown. Do the library assignment.

9/20 Experiment - Saponification, Soaps & Detergents, Experiment 3 - QUIZ on "Identifying an Unknown" (physical properties, attractive forces) and "Soaps", Read "titration" on ChemPages, Theory: define saponification, hydrolysis, esterification give overall reaction, define "salting out", hard water, emulsifying agent, pH, titration MSDS: water, ethanol or ethyl alcohol, sodium hydroxide, calcium chloride, iron chloride (or ferric chloride), magnesium chloride. Theoretical Yield of soap is 23g. In your conclusion, describe the yield and % yield, the properties of your soap and how it compared with commercial soap and detergent. Answer the 9 questions at the end of the experiment.

9/27 Experiment - Alum from Waste Aluminum Cans, Experiment 4 - Also read the 1st page of Experiment 6, Preparation of Alcohol - you will need to start that today. QUIZ on "Soaps", "titration" on ChemPages and “Aluminum”, Theory: give overall reaction, define limiting reagent, actual yield, theoretical yield, percent yield, moles, molarity MSDS: aluminum, potassium hydroxide, sulfuric acid, ethanol. Conclusion: What was the yield and %yield of alum. Describe your product and how well the reaction went. Any problems? Questions: answer the 7 pre-lab and 3 post-lab questions.

10/4 Experiment - "Analysis of Lead Samples" Experiment 5 Bring PAINT CHIPS and VINEGAR from mug, QUIZ on "Aluminum" (Some Sample Questions) and "Lead" (Hazards?) Theory:define gravimetric and spectrophotometric analysis, precipitation MSDS: nitric acid, sodium sulfite, potassium iodide, acetic acid, potassium chromate, All lead must go into the toxic metal waste bottle (you will lose points if you do not dispose of the lead waste correctly). All potassium chromate must go into the chromium waste bottle (you will lose points if you do not dispose of the chromium waste correctly). Conclusion: Did you find lead in either sample? Was it within acceptable limits? Describe how effective gravimetric and spectrophotometric analysis were. Questions: answer the 6 post-lab questions.

10/11 Experiment - "Preparation and Analysis of Alcohol" Experiment 6 Show points #7,8,& 9 in your graph (draw them in - use a ruler). Make sure you calculate the concentration of #7,8,&9 and discuss the concentration of your fermentation product in your conclusion. Read ChemPages on Gas Chromatography, QUIZ on "Lead" (reactions, centrifuge, spectronic 20, gravimetric & spectrophotometric analysis, answers to questions, etc.) and "Alcohol" (Hazards?) Theory: give overall reaction, define fermentation, GC, MSDS: ethanol, potassium dichromate, silver nitrate, sulfuric acid All potassium dichromate must go into the chromium waste bottle (you will lose points if you do not dispose of the chromium waste correctly). Conclusion: How much alcohol did you collect? What was the percentage of alcohol in the fermentation product? in the distillation product? (make sure you show your calculations for #7,8 & 9 using the formula for the line from your graph) Questions: Answer 2 Pre-Lab Questions, Page 2 and 6 questions at the end of the experiment

10/18 Experiment - "Unsaturation in Foods" Experiment 7 QUIZ on "Preparation and Analysis of Alcohol" ( Read ChemPages on Gas Chromatography; reactions, answers to questions, etc.) and "Unsaturation in Foods" (Hazards?) Theory: soxylet extractor, petroleum ether, ligroin, saturated and unsaturated fats, cis, trans, hydrogenation, isomerization MSDS: methylene chloride, bromine All methlyene chloride must go into the halogentated organic waste bottle (you will lose points if you do not dispose of the methylene chloride waste correctly). Conclusion: Which of the fats were the most saturated? Explain. How do your results compare with the group results? Explain any differences. Questions: Answer the 7 questions at the end of the lab.

10/25 Experiment - "Vitamin C Analysis" Experiment 8 QUIZ on "Unsaturation in Foods" (definitions, etc.) & "Vitamin C Analysis" Theory: define titration, vitamins, minerals MSDS: iodine, starch, hydrochloric acid. The titration waste must go into the Iodine waste bottle. Conclusion: What was the concentration of vitamin C in the fruit juice? Explain. How do your results compare with the group results? Explain any differences. Questions: Answer the 8 questions at the end of the experiment.

11/1 Experiment - "Acidity" Experiment 9 QUIZ on "Vitamin C Analysis" (definitions, etc.) and "Acidity" (hazards) Theory: Define pH, acid, base, hydronium ion, buffer, logarithm MSDS: acetic acid, sodium acetate, hydrochloric acid, sodium hydroxide Conclusion: Which products were more acidic and which were more basic. Can you give any reasons why? Based on the experiment, what is the advantage of a buffer? Address the comments at the end of your experiment. How do your results compare with the group results? Explain any differences. Questions: Answer the 6 Pre-Lab Questions (Remember: pH = -log[H⁺]. Therefore to calculate [H⁺], change the sign of the pH and use 10^x on your calculator where x is -pH. pOH = 14 - pH and pOH = -log[OH^-]. To calculate [OH^-], first calculate pOH, change the sign of the pOH and use 10^x on your calculator where x is -pOH.) and the 6 Post-Lab Questions at the end of your experiment

11/8 Experiment - "Paper Chromatography" Experiment 10 QUIZ on "Acidity" (Be prepared to do calculations with pH as discussed in lab, dilution, buffer, pH indicators, etc.) and "Paper Chromatography" (hazards) Theory: Define chromatography and the different types of chromatography (paper, TLC, GC, column, LC) MSDS: sodium chloride, acetone Conclusion: How effective was paper chromatography in separating the components in the mixtures? Which solvent was more effective? Why? Questions: Answer the 3 questions at the end.

11/15 Experiment - "Polymerization" Experiment 11 Turn in Science Fair Powerpoint Warning: Do Not Heat a Sealed Container!!!!!QUIZ on "Paper Chromatography" (principles and types of chromatography, etc.) and "Polymerization" (hazards) Theory: Define polymer, monomer, addition, condensation, thermoplastic, thermosetting, crosslinking MSDS: styrene, benzoyl peroxide, adipoyl chloride, sodium hydroxide, borax, polyvinyl alcohol, polyvinyl acetate, toluene Conclusion: Describe the properties of the different polymers you made and used in this experiment. Compare them to each other. Questions: answer the 7 post-lab questions. All students will need to clean their glassware and check out of their drawer.

11/22 Experiment - QUIZ on "Polymerization" (definitions, reactions) Science Fair Project. Students will give a 10 minute PowerPoint presentation of a proposed science fair project and answer questions. Students should critique the experiment. A good set of critical thinking criteria is FLaReS (falsifiability, logic, replicability, sufficiency), which is described on page 27 of Chemistry for Changing Times, Hill & Kolb. Turn in Portfolio.

11/29 Students who have missed a lab, will take the Cumulative Final Exam. All students will need to clean their glassware and check out of their drawer.

Criteria for evaluating science fair project:

Name

Question Defined

Experiment Defined

Data Collected

Logical?

Replicable?

Sufficient?

Time (10 min)

Presentation

Grade (0-100 points)

List of MSDS

http://www.chemexper.com/index.shtml?main=ccd/ccd_from_web.html

http://chemfinder.camsoft.com

http://themerckindex.cambridgesoft.com/

http://msds.ehs.cornell.edu/msdssrch.asp

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