DOC PREVIEW
UCLA CHEM 20L - kinetics_postlab_new

This preview shows page 1 out of 2 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 2 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 2 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Chemistry 20LWinter 2006Post-lab WorkChemistry 20LWinter 2006Chemistry 20L Winter 2006 Report Guidelines for Kinetics Study of Red Food Color with Bleach (The Assignment is provided as a handout.) Post-lab Work (This is a GROUP report. TURN IN ONLY ONE POST-LAB REPORT PER GROUP. ) Before preparing your report, you will need to complete the Kinetics Excel Tutorial Workshop. A room has been reserved in the Chapman Science Learning Center during your second lab period if you complete your data collection before the end of the period. Otherwise, you will need to work through the tutorial on your own. You will be expected to present the data and graphs for this report in the format described in the tutorial. You will turn in the self-evaluation forms from the tutorial handout with your report. Introduction: In a brief introductory paragraph or organized table indicate what each person was responsible for in both the performance of the experiment and the report. Each person must sign the report next to the description of his or her responsibilities. Data Calculations and Discussion: Serial Dilution • Provide a table for your final serial dilution procedure including the measured absorbance of each solution and the calculated molar concentration. The molecular weight of FD&C Red #3, which is 879.9 g/mol. Briefly describe any changes you made from your original plan. Rate Trial Scheme • Provide a table of your final rate trial scheme with a brief description of any changes you made from your original plan. Rate Trials • Using Beer’s Law, A = εbc, determine the molar absorptivity for FD&C Red #3. Use the concentration and absorbance of your final dilution and assume the diameter of the culture tube (that is, the path length) is 1.00 cm. • Calculate the initial concentration of dye in each rate trial. This is the concentration at time = 0 • Set up a spreadsheet table for each trial that you used for analysis. Make sure the headings for each table reflects the experimental conditions for the trial. Label the columns, time, Absorbance, [dye], ln [dye], 1/[dye]. Note: [ ] means concentration in mol/L. • Calculate the data for each cell. (Note: Use the measured absorbance of the solution during the trial, the calculated extinction coefficient for the dye, and a path length of 1cm to determine the [dye] during the rate runs.)Chemistry 20L Winter 2006 Report Guidelines for Kinetics Study of Red Food Color with Bleach (The Assignment is provided as a handout.) Briefly explain, if applicable, why trials that you performed were not used in the subsequent analysis. Using your spreadsheet data, prepare three graphs for each trial: • [dye] vs. time • ln[dye] vs. time • 1/[dye] vs time. Be sure to title your graphs, and label the axes including units. EACH of your graph MUST include a legend for the experimental condition of EACH TRIAL. Print EACH graph on a separate piece of paper. Rate Data Analysis: • From a visual inspection of these plots, select the linear relationships to establish a, the order of the reaction with respect to the dye. Explain how you arrived at your value. • Using the plots that give linear relationships, determine the rate constant for each trial. Refer to page 2 and 3 of the handout. • By comparing the slopes of the lines for various trials, determine b, the order of the reaction with respect to hypochlorite. Refer to page 2 and 3 of the handout. Error Analysis: • Calculate the average value for your rate constants and the percent relative error. • If sufficient data is available, calculate the average value for b, the order of the reaction with respect to hypochlorite and the percent relative error. “ • Is your range of values for b consistent with a “whole number” for the order of the reaction? • If you have only one value for b, what percent error would let you deduce that experimentally this is a “whole number?” Conclusions: Summarize your results and the justifications for using the plots you did to determine the order of the reaction. Write your experimental rate law based on the order of the dye and the order of the sodium hypochlorite that you obtained in your calculations. Kinetics studies can disprove a proposed mechanism, but can never prove a mechanism. Explain whether the results that you have obtained are consistent with the mechanism proposed on page 2 of this


View Full Document

UCLA CHEM 20L - kinetics_postlab_new

Documents in this Course
Exam 1

Exam 1

1 pages

Load more
Download kinetics_postlab_new
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view kinetics_postlab_new and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view kinetics_postlab_new 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?