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Kinetics Activity Handout Form: Step-1

This document provides instructions and data for students to analyze kinetics experiments involving the reaction of dyes (blue dye and red dye) with bleach. Students are asked to: 1) Analyze kinetics data to determine rate constants and rate laws for the reaction of each dye with bleach. 2) Use absorbance measurements at different dye concentrations to determine the proportionality constant in Beer's Law. 3) Analyze kinetics traces from experiments with varying concentrations of blue dye and bleach to determine the rate law and rate constant for that reaction. The same is done for the reaction of red dye and bleach.

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Harshil Tejani
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223 views5 pages

Kinetics Activity Handout Form: Step-1

This document provides instructions and data for students to analyze kinetics experiments involving the reaction of dyes (blue dye and red dye) with bleach. Students are asked to: 1) Analyze kinetics data to determine rate constants and rate laws for the reaction of each dye with bleach. 2) Use absorbance measurements at different dye concentrations to determine the proportionality constant in Beer's Law. 3) Analyze kinetics traces from experiments with varying concentrations of blue dye and bleach to determine the rate law and rate constant for that reaction. The same is done for the reaction of red dye and bleach.

Uploaded by

Harshil Tejani
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 5

Kinetics Activity Handout Form

Name: __________________________________________ Date:__________________________

Note: You are strongly encouraged to use a spreadsheet program (excel), or other mathematical program (matlab, Mathcad,
mathematica, R etc.) to complete this assignment. The blackboard site has links to a video introducing excel, along with excel
spread sheets that contain the data for question 3.

1) (4 pts) This form accompanies the online kinetics activity. Please use it to answer the following questions:
Step-1
a) Attach the printout of your kinetic trace and fill in the following data table:

Volume of dye solution


Concentration of bleach solution
Volume of bleach solution

b) What are the initial concentrations of [Dye] and [Bleach] for your experiment?

Step-2
c) What is the value of the pseudo rate constant for your experiment?

Step-3
d) Design an experiment to determine the order of the reaction with respect to [bleach]. Attach a printout of your kinetic
trace from your experiment. Give the order with respect to [bleach] and explain how you determined this from the
experiment.

Page 1 of 5
Step-4
e) What is the proportionality constant, ε l, in Beer’s law, abs = ε l [dye]? Include units in your answer. (Abs is unitless and
[dye] is in mol/L or M.)

f) Calculate the rate constant (k) for the reaction of Yellow 6 with bleach to 2 significant figures, assuming the concentration
of [dye] and [bleach] are in M. Write the rate law for the reaction (including both the numerical value of k, and the order
of the reaction with respect to [dye] and [bleach]).

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3) (4 pts total) The following shows results from experiments similar to those of the online tutorial, but with different dyes and bleach.
The reaction has 1:1 stoichiometry.

dye + bleach  colorless products

The initial solutions have the following concentrations


Blue dye: 3.20 x 10-5 M Red dye: 5.60 x 10-5 M Bleach: 0.150 M

The absorbance was measured at various dye concentrations and the results are summarized below. (Note: This data also available in
the file: http://collective.chem.cmu.edu/kinetics/documents/dyeData.xlsx )

[blue dye] abs [red dye] abs


0 0 0 0
3.20E-06 0.08 5.60E-06 0.085
6.40E-06 0.16 1.12E-05 0.17
9.60E-06 0.24 1.68E-05 0.255
1.28E-05 0.32 2.24E-05 0.34
1.60E-05 0.4 2.80E-05 0.425
1.92E-05 0.48 3.36E-05 0.51
2.24E-05 0.56 3.92E-05 0.595
2.56E-05 0.64 4.48E-05 0.68
2.88E-05 0.72 5.04E-05 0.765
3.20E-05 0.8 5.60E-05 0.85

Page 3 of 5
Experiments were then performed by mixing the following volumes of dye and bleach solutions and monitoring absorbance versus
time.

Experiment 1: blue dye: 9.50 mL bleach: 0.500 mL


Experiment 2: blue dye: 9.00 mL bleach: 1.00 mL
Experiment 3: red dye: 9.50 mL bleach: 0.500 mL
Experiment 4: red dye: 9.00 mL bleach: 1.00 mL

The results of the experiments are available in the


dyeData.xls excel file accompanying this homework, and are
plotted to the right.

a) (2 pts) Determine the rate law of the reaction (including the rate constant, and order with respect to [dye] and [bleach]):

blue dye + bleach  colorless products

Please describe your approach, including any calculations or plots used for the analysis.

Page 4 of 5
b) (2 pts) Determine the rate law of the reaction (including the rate constant, and order with respect to [dye] and [bleach]):

red dye + bleach  colorless products

Please describe your approach, including any calculations or plots used for the analysis.

Page 5 of 5

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