1. Spectrophotometry For high school Chemistry, AP Chemistry,
AP Biology and Astronomy
By: Babette Shoemaker, MT
Math and Science Academy at Ocean Lakes High School
Virginia Beach, VA
Website: zadosci.com

2. Spectroscopy: The branch of science concerned with the investigation and measurement of spectra produced when matter interacts with or emits electromagnetic radiation. 
Spectrophotometry: The quantitative measurement of the reflection or transmission properties of a material as a function of wavelength.

3. AP Chemistry Objectives: Essential Knowledge: 1. B
AP Chemistry Objectives: Essential Knowledge: 1.B.1 Learning Objective: 1.7, 1.15 Science Practice: SP 1.3, SP 1.5, SP 3.3 Great Instructions: Analog Spec20 Instructions

4. The basic set-up for a spectrophotometer:

5. Absorbance: the measurement of the attenuation of photons as light passes through a sample. Transmittance: the measurement of the amount of photons that pass through a sample.

6. Analog Spec20

7. Vernier Spectro-Vis:

8. PASCO Spectrophotometer:

9. Color and Wavelength
Why do you think the main peak for blue Gatorade is in the orange/red zone?
2. Why is there no/little absorbance in the blue zone?
3. What do you think caused the violet peak for the green Gatorade? How do you know?

10. Beer’s Law: A =  l C Where: A = absorbance (no units)  = Molar Aborptivity (unit is M-1cm-1) l = cell length (unit is cm) C = concentration (unit is M)
Molar Absorptivity = also known as the molar extinction coefficient = A measure of how strongly a chemical species absorbs light at a particular wavelength.

11. Calibration Curve:  or standard curve, a curve that has been established by the testing of known concentration standards that can be used to determine the concentration of a substance in an unknown Calibration Curve for Substance X Concentration

12. Beer’s Law Lab The students will: - practice serial dilution - calibrate the spectrophotometer - determine the optimal wavelength or max - collect and record absorbance for dilutions - construct a calibration curve - determine the concentration of an unknown liquid using their calibration curve

13. Changes to the lab for today:
We will be:
using red food coloring in water as our solution.
performing a serial dilution, 1:2, 1:4, 1:8 and1:16.
determining the optimal wavelength from the Spectrovis.
Creating the calibration curve using the free app from Vernier – Graphical Analysis

14. Serial Dilution:
add add add add add
1: : : : :16
Original
1:1

15. Resources:
they have great lab manuals for all levels and courses
Lab-Chlorophyll-With-SpectroVis
yllandvisiblelight.pdf
copy_Beer's_Law.pdf

16. Citations:
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oscopy.pdf
course-and-exam-description.pdf