Access over 20 million homework & study documents
search

Absorption Spectroscopy Identify Concentration of Two Cobalt Solution

Content type

User Generated

Subject

Chemistry

Type

Worksheet

Rating

Showing Page:
1/3
Absorption Spectroscopy of Unknowns
Purpose: To identify the concentrations of two cobalt solutions.
Procedure:
Obtain a Stock solution of Cobalt, and make three (3) dilutions for use in a set of standards.
Using an approximately 0.5M Stock Solution prepare three standards approximately (0.2M, .1M,
and 0.05M). In conjunction with a blank at 0M prepare a calibration curve.
1. Obtain several milliliters of distilled/deionized water in a clean small beaker
2. Obtain a three (3) clean, dry 25.00-mL volumetric flasks
3. Using a pipet, take necessary aliquots to prepare the Standard solutions, and dilute all to
25mL
4. Thoroughly mix all three dilutions and set aside.
5. Obtain an unknown
Set up the spectrometer and set to the specified wavelength
1. Obtain a cuvette and perform a blank using distilled water (0M), Calibrate the
spectrometer so that the absorbance of the blank is “0”
2. After emptying the cuvette poor a small aliquot of the lowest concentration solution and
place it in the spectrometer, record its absorbance.
3. Repeat this for each of the other standards and the stock solution. Absorbances for the
concentrations should go up with respect to concentration.
The incident light Io passes through the sample, the more particles present, the higher the
absorption of the energy will be, the transmitted light will be the remaining light that reaches the
detector. The instrument will measure the difference between the incident light and the
transmitted light, which will be a function of concentration.
4. Once the absorbance of the blank, three standards and stock solution have been recorded,
record the absorbance of the unknown solution.
5. Enter data into the class data set

Sign up to view the full document!

lock_open Sign Up
Showing Page:
2/3
Since this is group lab no individual calibration curve will be conducted. Though your data can
be validated individually and should look similar to the following calibration curve:
Data:
Section A RAW DATA
In the data table you will find the stock solution concentration of 0.42M. Three dilutions were
made from the stock solution (A, B, and C) the volume of the stock solution used is listed for
each solution. The total volume is 25mL. The Absorbance of the Unknown is also given in this
section as no calculations were required obtain it.
Section B
The Calculated concentrations of each dilution are provided here. These values make up the
calibration curve (X Axis)
Section C
The absorbance of each solution of the calibration curve is provided here. These values make up
the calibration curve (Y Axis)
Section D
The Calibration curve data is given here, all values are calculated in excel rather than plotted on
a physical graph. The slope (m), the intercept (B) and R-squared value (evaluation of how linear
the data set is) With the absorbance of the unknown (Y Value) the X Value of the Unknown
Concentration could be calculated. The equation for a line is Y = mX + B.

Sign up to view the full document!

lock_open Sign Up
Showing Page:
3/3

Sign up to view the full document!

lock_open Sign Up

Unformatted Attachment Preview

Absorption Spectroscopy of Unknowns Purpose: To identify the concentrations of two cobalt solutions. Procedure: Obtain a Stock solution of Cobalt, and make three (3) dilutions for use in a set of standards. Using an approximately 0.5M Stock Solution prepare three standards approximately (0.2M, .1M, and 0.05M). In conjunction with a blank at 0M prepare a calibration curve. 1. Obtain several milliliters of distilled/deionized water in a clean small beaker 2. Obtain a three (3) clean, dry 25.00-mL volumetric flasks 3. Using a pipet, take necessary aliquots to prepare the Standard solutions, and dilute all to 25mL 4. Thoroughly mix all three dilutions and set aside. 5. Obtain an unknown Set up the spectrometer and set to the specified wavelength 1. Obtain a cuvette and perform a blank using distilled water (0M), Calibrate the spectrometer so that the absorbance of the blank is “0” 2. Af ...
Purchase document to see full attachment
User generated content is uploaded by users for the purposes of learning and should be used following Studypool's honor code & terms of service.

Anonymous
Just the thing I needed, saved me a lot of time.

Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4