Chem142_Kinetics1_Report_Gradescope_051621_Mac
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University of Washington *
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Course
CHEM 142
Subject
Chemistry
Date
Feb 20, 2024
Type
Pages
7
Uploaded by JusticeQuail3324
Page 1 of 7
Name:
Abel Tecomahua
Quiz Section:
CK
Lab Partner: Nick Strable
Student ID#:
2229544
READ THIS BEFORE PROCEEDING WITH THE DATA ANALYSIS FOR THIS EXPERIMENT:
For this lab, you will first evaluate the data for the CV
+
standards to obtain a value for molar absorptivity (
e
) that you will then use to convert Absorbance data to [CV
+
] (Remember: A=
e
l
c;
if
the calibration curve does not go through 0,0 then you need to include the y-interecept in your calculation of the concentration). You will then evaluate the concentration data as a function of time using the integrated rate law method of determining the orders with respect to each reactant and the rate contant for the reaction at this temperature.
You will plot all of the data for the calibration curve and for Run 1. However, for the data in Runs 2-4 and the determination of the order with respect to OH
-
, INSTEAD OF CREATING ADDITIONAL PLOTS, WE WILL USE A SHORTCUT THAT EMPLOYS FUNCTIONS WITHIN EXCEL TO DETERMINE THE SLOPE AND Y-INTERCEPT FOR A SET OF DATA. For example, to use these functions, click on the cell in which you want the result to appear and enter the following:
=SLOPE(A10:A15,B10:B15) =INTERCEPT(A10:A15:B10:B15) In this example,
A10:A15 represent an the cells that contain data for the y-axis and B10:B15 represent data for the x-axis. This is a shortcut for generating the slope and y-intercept values without actually creating a plot of the data and generating the trendline equation of y = mx + b. You will create three plots on page 4, using the data from Run 1, to determine the order of the reaction with respect to CV
+
. Once you know the order of the reaction with respect to CV
+
, you will perform the necessary "slope" functions for the other three runs to determine k' for each run. When you get to the section for determining the order of the reaction with respect to OH-, you will also need to use the "intercept" function mentioned above.
CHEM 142 Experiment #5: Kinetics I (Integrated Rate Law)
Goals of this lab:
•
Create and use a calibration curve for the absorbance/concentration relationship for crystal violet
•
Evaluate absorbance versus time measurements to determine the order of a reaction
•
Analyze graphs of data to determine best linear fit
•
Calculate rate constants from best-fit lines and values
•
Assemble a complete kinetic description of the reaction from data gathered
Your lab report will be grade on the following criteria using a poor/good/excellent rating system (see the Self-
Assessment on the “Reporting Your Results for Exp #5” page of the lab website for more details):
•
Calculations are accurate and complete based on data gathered; proper significant figures and units are used
•
Data collected is reasonable; outliers are identified and possible explanations are reasonable
•
Interpretations of graphs and data are reasonable
•
Reaction orders are determined accurately from data gathered; reasonable conclusions are reached
•
All graphs and tables and clearly and accurately labeled; entire report is typed
By signing below, you certify that you have not falsified data, that you have not plagiarized any part of this lab report, and that all calculations and responses other than the reporting of raw data are your own independent work. Failure to sign this declaration will result in 5 points being deducted from your lab score.
Signature: __________Abel Tecomahua______________________________
This lab is worth 60 points: 10 points for notebook pages, 50 points for the lab report
(Do NOT include your notebook pages when you scan your report for upload into Gradescope.)
Page 2 of 7
NAME:
QUIZ SECTION:
Part I. Determining the Molar Absorptivity for Crystal Violet
Concentration of stock solutions
Volume of CV
+
stock solution needed
CV
+
1.0E-04
M
to make 25 mL of 1.0 x 10
-5
M CV
+
is
OH
-
0.10
M
CV
+
2.5
mL
Calibration Curve Data
l
max, CV
+ 582.3
nm
Dilution Factor
[CV
+
] (M)
Absorbance
10.0
1.0E-06
0.073
4.0
2.5E-06
0.217
2.0
5.0E-06
0.379
1.0
1.0E-05
0.786
Slope of Absorbance versus concentration graph
77989 M
-1
y-intercept of Absorbance versus concentration graph
0.0030
Detailed calibration equations:
FROM THIS REPORT:
FROM THE LQ2 SYSTEM IN LAB:
If the slope = e
l
, what is the molar absorptivity for the CV
+
at this wavelength?
77989
M
-1
cm
-1
(Note: if you have two different values based on two different calibration curves, use the
equation that is based on your data analysis here in the Excel template, not the one from lab.)
Absorbance=77989([CV+]M)0.0030
molar absorptivity, e
Absorbance=77977([CV+]M)0.0029071
Note: All sections of this report must be typed
y = 77989x + 0.003
R² = 0.9978
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
Absorbance at 582.3 nm
CV+ Concentration (M) Calibrations Curve for CV+ Standards
Page 3 of 7
NAME:
QUIZ SECTION:
Part II. Determining the Rate Law for the CV
+
+ OH
-
Reaction
Table of Volumes and Final Concentrations During Solution Preparation for Runs 1-4
Run #
mL of 0.1 M NaOH
mL of DI H
2
O
mL of 3.0 x 10
-5
M CV
+
mL Total
[CV
+
]
final
, M
[NaOH]
final
, M
1
2
0.5
0.5
3
5.00E-06
0.0667
2
1.5
1
0.5
3
5.00E-06
0.0500
3
1
1.5
0.5
3
5.00E-06
0.0333
4
0.5
2
0.5
3
5.00E-06
0.0167
*[CV+]
final
and [NaOH]
final
are the final concentrations after all reagents are mixed
and the initial concentration for the start of the reactions
slope
units for slope
y-intercept
Student- specific data from pg 2 used in calculations autofill here:
77989
M
-1
0.0030
Run 1
Time (s)
Absorbance
[CV+]
t
ln[CV+]
t
1/[CV+]
t
10
0.396
5.04E-06
-12.198
1.98E+05
ORDER WITH RESPECT TO CV
+
20
0.348
4.42E-06
-12.329
2.26E+05
Which plot (on the next page) is the most linear?
30
0.336
4.27E-06
-12.364
2.34E+05
40
0.301
3.82E-06
-12.475
2.62E+05
50
0.289
3.67E-06
-12.516
2.73E+05
60
0.268
3.40E-06
-12.593
2.94E+05
70
0.241
3.05E-06
-12.700
3.28E+05
80
0.220
2.78E-06
-12.792
3.59E+05
90
0.203
2.56E-06
-12.874
3.90E+05
100
0.189
2.38E-06
-12.947
4.19E+05
110
0.172
2.17E-06
-13.042
4.62E+05
RUN #1
120
0.153
1.92E-06
-13.162
5.20E+05
130
0.140
1.76E-06
-13.252
5.69E+05
140
0.132
1.65E-06
-13.313
6.05E+05
150
0.122
1.53E-06
-13.393
6.56E+05
160
0.107
1.33E-06
-13.528
7.50E+05
ln[CV+] vs time
first order
Based on the plots you created on the next page, what is the order of this reaction with respect to CV
+
?
-0.00860
What is the value of the slope for the most linear plot?
What is the psuedo-rate constant (k') for this reaction?
8.60E-03
Show your calculation of the [CV
+
] at the first timepoint in Run #1
:
77989([CV+]M)0.0030=Abs
0.396=77989([CV+]M)0.0030
0.393=
77989([CV+]M)
[CV+]=5.04E-06 M
READ THIS BEFORE PROCEEDING For evaluating the data for Run 1, enter your time and absorbance values, as recorded in your lab notebook during lab, in columns A and B, respectively. In column C, convert the aborbance values to concentration according to the example you provided at the top of this page. In column D, convert the [CV
+
] values from column C to ln [CV
+
]. In column E, convert the [CV
+
] values from column C to 1/[CV
+
]
.
Insert
the plots used to determine the order with respect to [CV
+
] on the next page, then come back and provide the summary information as requested.
Reaction Order Determination for CV
+
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Page 4 of 7
NAME:
QUIZ SECTION:
Place your plot of [CV+] vs time here,making it large enough to cover this box (so that it is easy to read).
FOR FULL CREDIT:
- plot the correct data on each axis
- correctly label each axis and format the axis such that the data being plotted fills the majority of the graph (axes do NOT need to start at 0)
- appropriately title the plot
- use Excel to add a trendline for the data...be sure to choose the trendline options that "display equation on chart" and "display R-squared on chart"
y = -2E-08x + 5E-06
R² = 0.9777
0.00E+00
1.00E-06
2.00E-06
3.00E-06
4.00E-06
5.00E-06
6.00E-06
0
20
40
60
80
100
120
140
160
180
[CV+]t
Time(s)
Determination of Zero Order Reaction y = -0.0086x - 12.107
R² = 0.9968
-13.600
-13.400
-13.200
-13.000
-12.800
-12.600
-12.400
-12.200
-12.000
0
20
40
60
80
100
120
140
160
180
ln[CV+]t
Time(s)
Determination of 1st Order Reaction
y = 3467.6x + 114388
R² = 0.9558
0.00E+00
1.00E+05
2.00E+05
3.00E+05
4.00E+05
5.00E+05
6.00E+05
7.00E+05
8.00E+05
0
20
40
60
80
100
120
140
160
180
1/[CV+]t
Time(s)
Determination of 2nd Order Reaction
Page 5 of 7
NAME:
QUIZ SECTION:
Run 2
Run 3
Time (s)
Absorbance
[CV+]
t
f ([CV
+
]
t)
Time (s)
Absorbance
[CV+]
t
f
([CV
+
]
t
)
10
0.340
4.32E-06
-12.352
10
0.367
4.67E-06
-12.275
20
0.321
4.08E-06
-12.410
20
0.350
4.45E-06
-12.323
30
0.300
3.81E-06
-12.479
30
0.335
4.26E-06
-12.367
40
0.283
3.59E-06
-12.537
40
0.319
4.05E-06
-12.416
50
0.260
3.29E-06
-12.623
50
0.304
3.86E-06
-12.465
60
0.242
3.06E-06
-12.696
60
0.289
3.67E-06
-12.516
70
0.224
2.83E-06
-12.774
70
0.276
3.50E-06
-12.563
80
0.210
2.65E-06
-12.840
80
0.264
3.35E-06
-12.608
90
0.186
2.35E-06
-12.963
90
0.251
3.18E-06
-12.659
100
0.174
2.19E-06
-13.031
100
0.238
3.01E-06
-12.713
110
0.158
1.99E-06
-13.129
110
0.225
2.85E-06
-12.770
120
0.145
1.82E-06
-13.217
120
0.214
2.70E-06
-12.820
130
0.134
1.68E-06
-13.297
130
0.204
2.58E-06
-12.869
140
0.125
1.56E-06
-13.368
140
0.194
2.45E-06
-12.920
150
0.116
1.45E-06
-13.445
150
0.185
2.33E-06
-12.968
160
0.176
2.22E-06
-13.019
170
0.167
2.10E-06
-13.073
180
0.160
2.01E-06
-13.116
190
0.151
1.90E-06
-13.175
200
0.144
1.81E-06
-13.224
210
0.135
1.69E-06
-13.290
220
0.129
1.61E-06
-13.336
230
0.122
1.53E-06
-13.393
240
0.115
1.44E-06
-13.454
250
0.110
1.37E-06
-13.500
RUN #2
What is the value of the slope for the most linear plot?
What is the psuedo-rate constant (k') for this reaction?
RUN #3
What is the value of the slope for the most linear plot?
What is the psuedo-rate constant (k') for this reaction?
-0.00807
8.07E-03
-0.00512
5.12E-03
Page 6 of 7
NAME:
QUIZ SECTION:
Run 4
Time (s)
Absorbance
[CV
+
]
t
f
([CV
+
]
t
)
10
0.420
5.35E-06
-12.139
RUN #4
20
0.409
5.21E-06
-12.166
What is the value of the slope for the most linear plot?
30
0.400
5.09E-06
-12.188
40
0.390
4.96E-06
-12.214
50
0.380
4.83E-06
-12.240
60
0.370
4.71E-06
-12.267
What is the psuedo-rate constant (k') for this reaction?
70
0.361
4.59E-06
-12.292
80
0.351
4.46E-06
-12.320
90
0.343
4.36E-06
-12.343
100
0.334
4.24E-06
-12.370
110
0.325
4.13E-06
-12.398
120
0.316
4.01E-06
-12.426
130
0.308
3.91E-06
-12.452
140
0.300
3.81E-06
-12.479
150
0.293
3.72E-06
-12.502
160
0.285
3.62E-06
-12.530
170
0.278
3.53E-06
-12.555
180
0.272
3.45E-06
-12.578
190
0.264
3.35E-06
-12.608
200
0.258
3.27E-06
-12.631
210
0.252
3.19E-06
-12.655
220
0.245
3.10E-06
-12.683
230
0.238
3.01E-06
-12.713
240
0.232
2.94E-06
-12.739
250
0.226
2.86E-06
-12.765
260
0.221
2.79E-06
-12.788
270
0.215
2.72E-06
-12.816
Run #
[OH
-
]
k'
ln[OH
-
]
ln(k')
280
0.209
2.64E-06
-12.844
1
0.0667
8.60E-03
-2.708
-4.75599308
290
0.204
2.58E-06
-12.869
2
0.0500
8.07E-03
-2.996
-4.8196018
300
0.199
2.51E-06
-12.894
3
0.0333
5.12E-03
-3.401
-5.27460084
310
0.193
2.44E-06
-12.925
4
0.0167
2.63E-03
-4.094
-5.94077143
320
0.188
2.37E-06
-12.952
330
0.183
2.31E-06
-12.979
slope
0.899
340
0.178
2.24E-06
-13.008
y-int
-2.23
350
0.174
2.19E-06
-13.031
360
0.169
2.13E-06
-13.060
Order of the reaction with respect to [OH
-
]:
First Order
Rate constant for the overall reaction, k:
0.108
Units for k:
M^-1s^-1
-0.00263
2.63E-03
ln(k') vs. ln([OH
-
])
autofill from earlier in report
Values for [OH
-
] and k'
Reaction Order Determination for OH
-
Show your calculation of the rate constant for the overall reaction.
ln(k)=y intercept k=e^(y intercept)
k=e^(-2.23)
k=.108
Consult the "Helpful Information" section in the introductory pages for this experiment in the lab manual for help with this last section of data analysis. As explained in the Instruction box on page 1 of the template, for the slope and y-intercept calculations you will use the functions in Excel rather than creating a plot.
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Page 7 of 7
NAME:
QUIZ SECTION:
Results from earlier in the report autofill here:
Order wrt CV+
Unrounded Order wrt OH-
Overall rate constant
Units for overall rate constant
first order
First Order
0.108
M^-1s^-1
Results and Discussion 1. Based on your data, write the complete rate law, including the value and units for the rate constant. Rate=K[A][B]
Rate=0.108M^-1s^-1[CV+][OH-]
Laboratory Waste Evaluation Laboratory waste is considered anything
generated during an experiment that is disposed of down the sewer drain, thrown in the garbage, collected in a container for disposal by the UW Environmental Health & Safety department, or released into the environment. Based on the written lab procedure and
your actions during the lab, list the identity and approximate amount (mass or volume) of waste that you generated while performing this experiment. 6mL
of CH+ M-1
25mL of 1.05E-05 CV+
2mL of 3.0E-05M CV+
10 mL of 0.1M NaOH
50mL of Di water 2. The literature values of the orders with respect to CV
+
are and OH
-
are 1 and 1, respectively. Calculate your % error
for the experimental value for the order with respect to [OH
-
]. Discuss your largest sources of error.
%error=|0.108-1|/1=0.892*100=89.2 %error
The measurements of the solutions may have been off by the smallest amount, which could have resulted in a considerably different concentration. Additionally, the concentration may alter if we added too much or too little Di water.
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Here is the protocol for a UV-Vis spectrophotometer to detect water and chlorine-carbon.
1.Dissolve the water and chlorine-carbon compounds in a solvent, such as water.
2.Prepare a standard solution of known concentration that is similar to the sample being measured.
3.Calibrate the spectrophotometer using the standard solution.
4.Measure the absorbance of the sample using the spectrophotometer.
5.Calculate the concentration of the compounds in the sample using the calibration curve obtained from the standard solution.
How is the spectrophotometer calibrated with standard solutions? When is the blank solution placed in the spectrophotmeter?
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Table 1.0 of data showing calibration standards prepared by dilution and the absorbance
Concentration CuSO4 (M) Volume of 0.5M (ml) Volume of D/Water (ml) Absorbance
0.00
0.10
0.20
0.30
0.40
0.50
II.
0.00
1.00
2.00
3.00
4.00
5.00
5.00
4.00
3.00
2.00
1.00
0.00
1. Construct a graph of concentration against absorbance, clearly show a best fit line.
Find regression of your graph. Show how
0.000
0.406
0.638
0.854
1.202
1.276
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This was a fractional distillation lab separating cyclohexane and toluene. I know A in the NMR analysis is the aromatic component of toluene but I am having a hard time figuring out the other two peaks. Which one represents the methyl group of toluene and what is the other peak (it might be water or some other impurity)?
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Sally obtains a standard calibration curve for their assigned food dye by plotting absorbance versus concentration (in M) of known solutions and finds the following slope and intercept:
y = 1.646x + 0.026
Sally finds that her original Kool-aid sample is too concentrated, so they dilute it by transferring 13.00 mL of the original Kool-aid sample into a new container and diluting to a total volume of 37.00 mL. If the absorbance of the dilute Kool-aid sample at the appropriate wavelength for their assigned dye is 0.950, determine the concentration (in M) of the assigned food dye in the original Kool-aid sample. Report answer with three places after the decimal.
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