# Spectrophotometry Lab Report

Revised 6/15/17Name _________________________Station # ______ Date _____________________
CHM 101 Spectrophotometry
PRE-LAB
1. Calculate the molarities of diluted Copper (II) Sulfate solutions from the stock solution,
which is 0.1 M CuSO4.
Volume of CuSO4
Solution (mL)
Volume of DI H2O
(mL)
Molarity (M) of
Solution
Cuvette #1
0
5
Blank (0.0 M)
1
9
2
8
3
7
4
6
5
5
6
4
7
3
8
2
9
1
Cuvette#11
5
0
1.00 x 10-1
2. At what wavelength will the spectrophotometer be set?
3. The graph concentration vs. absorbance is associated with which Law?
Page 1 of 1
Revised 6/15/17
CHM 101 Spectrophotometry Experiment
Spectrophotometer wavelength set a 694nm.
Objective: to learn how to make dilutions from a given concentration (M1V1 = M2V2),
to learn how to plot a graph from data obtained and to gain some experience in the use of a
Spectrophotometer.
Background:
Spectrophotometric analysis is one method used to determine the concentration of a colored
substance in solution. Concentration is determined by calculating the amount of light that passes
through a sample and hits a detector. The more light that gets through, the less concentrated the
solution is (fewer molecules of the colored substance that absorb light).
A solution containing a colored substance absorbs a specific color (or colors) of visible light
and transmits the remaining colors. The amount of light a colored solution absorbs depends on
the concentration of the colored substance (mg/mL of solution). Another factor affecting the
amount of light absorbed is the color of light (wavelength in nm) selected.
A spectrophotometer is an instrument that measures the intensity of a light beam of a given
wavelength (color) that passes through a sample. Light of a given wavelength passes through
the sample, hits the detector, and the instrument can calculate the absorbance (A) of the
solution. If the appropriate wavelength is not selected, the sample will not absorb enough light
to make an accurate measurement.
Beer’s law states the absorbance is directly proportional to the concentration of a solution. If
you plot the absorbance (y-axis) versus the concentration (x- axis) you can determine the
concentration of an unknown solution using the graph or by using the equation for a line.
Beer’s Law is given by the equation
A = abC
in which, A = absorbance (measured with the Spectrophotometer)
a = constant (for a given substance at a given wavelength of light)
b = diameter of cuvette
C = concentration of absorber (CuSO4)
Safety Tips: Gloves, goggles and lab aprons must be worn. Please use caution.
Cuvettes must be transported to the spectrophotometer in a test tube rack.
Page 1 of 2
Revised 6/15/17
Experimental Procedure:
1. Each lab group will have an Erlenmeyer flask containing approximately 75mls of
0.1M CuSO4 on their lab table.
2. Label volumetric flasks #2-10 and cuvettes #1-11 using the wax pencil
provided.
3. Pipet desired amount of 0.1M CuSO4 solution in the labeled volumetric flask (see
Table 1 in Pre-lab). Then add de-ionized H2O from the squeeze bottle up to the line on
the volumetric flask. Cap the flask and invert at least “3” times to mix. Total
volume=10mls.
4. Transfer the solutions of CuSO4 from the volumetric flasks to the correct cuvette
(i.e. flask #2 to cuvette #2) and only fill the cuvettes half way.
5. For cuvette #1, fill it half way with de-ionized H2O and use it as the blank (to zero the
spectrophotometer); for cuvette #11, fill it half way with the 0.1M CuSO4 stock
solution.
6. Be sure to use a test tube rack to transport your cuvettes to the appropriate
Spectrophotometer (your Instructor will show you how to operate the
Spectrophotometer).
7. Use a clean Kimwipe to remove dirt, finger prints, etc. from each cuvette before
placing cuvettes in the sample holder of the Spectrophotometer.
8. At the conclusion of this experiment: be sure to remove cuvettes from the sample
holder, empty flask and cuvette contents into the waste container in fume hood “B”,
rinse flasks and cuvettes with water, use Windex cleaner to wipe down lab tables
and remember to wash your hands.
Page 2 of 2
Revised 6/15/17
Name _________________________Station # ______ Date _____________________
CHM 101 Spectrophotometry
Report Sheet
1. Absorbance of solutions of CuSO 4
Cuvette #
1
Molarity (from pre-lab)
2
3
4
5
6
7
8
9
10
11
Page 1 of 3
Revised 6/15/17
2. Check Beer’s law by plotting absorbance vs. Molar concentration on the graph.
Page 2 of 3
Revised 6/15/17
4. If Beer’s Law is valid, the value of “a” should be constant. Use A = abC or a = A/(bC)
and the data from the experiment to calculate values of “a” for the five solutions below.
The value of “b”, the diameter of the sample tube is normally 1 cm, so a = A/C in this
experiment.
Cuvette #
Calculated values for “a”
Average value for “a”
2
3
4
5
6
Page 3 of 3
Spectrophotometry
Make-Up Data
Instructions:
Use the following data to complete the data /calculation sheet of the experiment. Write your
weekly lab report for this lab, using this data and following the lab syllabus instructions.
1. Absorbance of solutions of CuSO 4
Cuvette #
1
0.00
Molarity (from pre-lab)
0.00
2
0.020
0.01
3
0.042
0.02
4
0.065
0.03
5
0.09
0.04
6
0.104
0.05
7
0.13
0.06
8
0.145
0.07
9
0.165
0.08
10
0.188
0.09
11
0.208
0.10
Revised 6/15/17
Name _________________________Station # ______ Date _____________________
CHM 101 Spectrophotometry
Post Lab Questions
1. If the wavelength is changed, what will happen to the absorbance values?
2. A CuSO4 solution has an absorbance value of 0.512. Use your graph Concentration vs.
Absorbance, determine the concentration of this solution.
Page 1 of 1

Don't use plagiarized sources. Get Your Custom Essay on
Spectrophotometry Lab Report
Just from \$13/Page
Calculate the price
Pages (550 words)
\$0.00
*Price with a welcome 15% discount applied.
Pro tip: If you want to save more money and pay the lowest price, you need to set a more extended deadline.
We know how difficult it is to be a student these days. That's why our prices are one of the most affordable on the market, and there are no hidden fees.

Instead, we offer bonuses, discounts, and free services to make your experience outstanding.
How it works
Receive a 100% original paper that will pass Turnitin from a top essay writing service
step 1
Fill out the order form and provide paper details. You can even attach screenshots or add additional instructions later. If something is not clear or missing, the writer will contact you for clarification.
Pro service tips
How to get the most out of your experience with Writall
One writer throughout the entire course
If you like the writer, you can hire them again. Just copy & paste their ID on the order form ("Preferred Writer's ID" field). This way, your vocabulary will be uniform, and the writer will be aware of your needs.
The same paper from different writers
You can order essay or any other work from two different writers to choose the best one or give another version to a friend. This can be done through the add-on "Same paper from another writer."
Copy of sources used by the writer
Our college essay writers work with ScienceDirect and other databases. They can send you articles or materials used in PDF or through screenshots. Just tick the "Copy of sources" field on the order form.
Testimonials
See why 20k+ students have chosen us as their sole writing assistance provider
Check out the latest reviews and opinions submitted by real customers worldwide and make an informed decision.
History
I got my essay 3 hours earlier, use this site instead of papersowl or edubirdie trust me I got scammed. This website is actually legit :) - Happy
Customer 455051, November 1st, 2021
Social Work and Human Services
I love how the writer pays attention to detail, this is allowing me great opportunity to learn even more from his writing styles!!
Customer 453933, October 1st, 2020
Other
I got an A in this project.
Customer 453877, February 6th, 2020
Statistics
I had to do major editing to the paper as there seemed to have lots of fluff in it. Nothing against the writer, I just know how the professor is and she will call it fluff. Tell the writer that overall good job done. Let's see what the grade will be. I will keep you posted. On to the next paper.
Customer 454329, October 1st, 2021
Education
Thank you!
Customer 455113, March 21st, 2022
Nursing
Customer 455057, March 2nd, 2023
Accounting
Outstanding!!
Customer 454639, March 30th, 2021
Exactly what I wanted to see in the paper. Thanks.
Customer 455001, October 20th, 2021
Education
Awesome service and amazing quality! I'll definitely be using it again when needed.
Customer 455113, November 15th, 2021
Customer 454811, January 11th, 2023
Social Work and Human Services
Excellent Job!!
Customer 453933, January 3rd, 2021
Sociology
This is an exceptional paper utilizing the sources provided. Thank you so much!
Customer 454953, October 14th, 2021
11,595
Customer reviews in total
96%
Current satisfaction rate
3 pages
Average paper length
37%
Customers referred by a friend