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Unformatted text preview: Spring 2007
Report Guidelines for Assignment #5 - Detergent Analysis Chemistry 20L Pre-lab work is always due at the beginning of the lab section. Pre-lab and post-lab reports must be written in your lab notebook (with the exception of graphs.) I. On-line Technique Videos & Resources For This Experiment Click on the title below to download the technique videos (Real Player required): (1) Laboratory Safety (this video was shown on the first day of the lab) (2) Use of a Buret If you have trouble downloading the videos, go to the following Web site and click on the appropriate title to download the video: www.oid.ucla.edu/Webcast/chemistry/index.html Additional resources for lab preparation and lab reports: (1) Theory on pH Meter and Electrode (pdf file) (2) Theory of Acid-Base Indicators (3) Soap & Detergent Chemistry
II. Pre-lab Report Guideline You must show up on time to your lab section with the proper safety attire. Students without proper laboratory safety protection will be dismissed from the laboratory. Any pre-lab reports that are not turned in within the first ten minutes of the lab section will not be accepted for grading. Your pre-lab report must include: (i) Heading: This includes the title of the experiment and date. (ii) Reference: Complete information of the references used for the experiment. (iii) Short Introduction: Summarize in a few sentences the background and the goal of the experiment. Outline the kinds of techniques that you will use in the experiment. (iv) Procedure: Flowchart format. (v) MSDS information Look up the following chemicals: HCl (3M), NaOH (0.5M) and Phosphoric acid (H3PO4) (1M) Provide: (a) Product Name (b) Chemical Formula (c) Formula Weight (d) Melting Point; Boiling Point and Density (e) Health Hazard Data (summarize in your own words) (f) Spill and Disposal procedures (summarize in your own words) *For your MSDS information, select the site that gives you the MSDS information closest to the concentration listed above. You may have to convert the concentration units on MSDS before you decide which site to use since sometimes the unit may be reported as w/v%. **Important: Reference the site (i.e. write down the URL address) that you used. Spring 2007 Chemistry 20L ***Record the MSDS info. in your lab notebook. (Web page print-outs will not be accepted!!) (vi) Pre-lab Assignment Complete instructions # 1-3 on page 64. Make sure that you separate the blank data tables from the rest of the pre-lab report. Show all work for any calculations and provide the appropriate units. III. Post-lab Report Guideline You are to do the lab in pairs and submit a group report. Turn in ONLY one post-lab report per group. Before starting your experiment and post-lab, please take a moment to review the guidelines for group work Accessible on VOH. (A) Data and Responsibilities (i) Write the responsibility of each group member for the experiment and lab report (ii) Recopy completed experimental data tables (including the color change of the universal indicator) (see p.65-66) (B) Data and Error Analysis (Show all work) Review the lecture guide for the topic on equivalent weight before completing the following items. (i) Calculate the % ash left in the detergent i.e. weight of ash / weight of sample detergent)*100% (ii) Determine the volume of NaOH required to titrate H2PO4 to HPO42(refer to the chemical reaction shown on p.64) (iii) Calculate the equivalents of hydroxide that are required to titrate the sample of H2PO4 to HPO42- (this is the number of equivalents of H+ transferred in the reaction, p.64) (iv) Determine the theoretical equivalent weight of H2PO4- in the titration reaction (v) Using the theoretical equivalent weight of H2PO4- and the equivalents of H+ transferred in the reaction, calculate the amount (in grams) of H2PO4- in your detergent sample (vi) Calculate the weight (in grams) of the detergent that can be attributed to phosphate (PO43- ) (vii) Determine the % phosphate in the original detergent sample (viii) Determine the % STPP in the detergent sample (C) Conclusions (i) Summarize your results (ii) Compare the % phosphate in detergent with the % ash. What can you conclude? Explain.
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