Chem 20L Fall 2006Chem 20L Fall 2006Definitions of Group Report and/or Group ExperimentChem 20L Fall 2006 Report Guidelines for Assignment #5 (Detergent Analysis) The pre-lab report is due at the beginning of the lab section. Refer to your laboratory syllabus for the due date of the post-lab report. Pre-lab and Post-lab reports MUST be written inside 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 video (require Real Player) (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. http://oid.ucla.edu/Webcast/Chemistry/ Theory on pH Meter Theory of Acid-Base Indicators Soap & Detergent Chemistry (II) Pre-lab Report Guideline IMPORTANT: Make sure that you follow the proper laboratory safety protocol (refer to the course syllabus) BEFORE going to the lab. You will be dismissed from the laboratory if you do not have the proper safety protocol. Please also make sure that you show up to the lab on time. Any pre-lab reports that are NOT turned in within the first ten minutes of the lab section will not be accepted for grading. (I) Introduction (II) Procedure in Flowchart Format & reference of procedure (III) MSDS information (refer to the MSDS handout for details) for the following chemicals HCl (3M), NaOH (0.5M) and Phosphoric acid (H3PO4) (1M) Note: Select the MSDS resource site that gives you the MSDS information closest to the concentration listed above for each individual chemical. 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%. You should record the following MSDS information in your notebook for the chemicals listed above. Printouts directly from Web pages will NOT be accepted for grading. Important: Reference the site (i.e. write down the URL address) that you used for each of the chemical. (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)Chem 20L Fall 2006 Report Guidelines for Assignment #5 (Detergent Analysis) (II) Pre-lab Report Guideline (Continued) (IV) Complete all the study questions # 1-3 on page 64. Follow instructions on p.64 (under "Pre-lab assignment") of your lab manual. (Make sure that you separate the blank data tables from the rest of the pre-lab report) IMPORTANT: Make sure that you show ALL YOUR WORK for any numerical calculations. Show all the units when working on pH calculation questions.CHEM 20L Fall 2006 Before attempting to work on the group post-lab report, please take a moment and read the following items carefully. Definitions of Group Report and/or Group Experiment (1) All members in the group MUST contribute equally when working on the experiment as well as writing the post-lab report (2) Each group member must prepare ahead of time when writing the reports. This means review materials from lectures or from your Chemistry textbook or from on-line resources on certain topics that are relevant to the concepts when writing the reports. Contribution to the group work is meaningless if a group member does not understand the concepts behind the experiment. (3) It is the responsibility of the group members to plan ahead on when they should get together to work on the report. In other words, maintain good communication between group members. (4) It is the responsibility of each group member to honestly describe the work that they did during the experiment and in writing the report. No one should take advantage of the other group member. Report to the course instructor or your TA if you feel that other group members are taking advantage of your work. (5) Each member in the group MUST understand the concepts behind the ENTIRE experiment regardless of which portions of the report or experiment a person is responsible for. This is especially important for the exams.Chem 20L Fall 2006 Report Guidelines for Assignment 5 (Detergent Experiment) Post-lab Reports MUST be written inside your lab notebook (II) Post-lab Report Guideline This is a GROUP report (i.e. ONE REPORT PER GROUP) (A) Data - write the responsibility of each group member during the experiment and in writing this report - recopy completed experimental data tables (including the color change of the universal indicator) into the post-lab report (see p.65-66) (B) Data and Error Analysis (YOU MUST SHOW ALL YOUR WORK) Review the lecture guide for the topic on equivalent weight BEFORE answering the following questions. - calculate the % ash left in the detergent (i.e. 100%*(weight of ash / weight of sample detergent) ) - determine the volume of NaOH required to titrate H2PO4- to HPO42-(refer to the chemical reaction shown on p.64) - 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)) - determine the theoretical equivalent weight of H2PO4- in the titration reaction - 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 - calculate the weight (in grams) of the detergent that can be attributed to phosphate ( PO43- ) - determine the % phosphate in the original detergent sample - determine the % STPP in the detergent sample (C) Conclusions - summarize your results - compare the % phosphate in detergent with the % ash. What can you conclude?
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