Questions and Answers
List the steps in the proper use of the spectrophotometer.
Turn it on with the button in the back. It will go through a three minute self-check. It takes 15 mins to warm up before measuring absorbance. Make sure it's set to absorbance mode by pressing A/T/C. Select desired wavelength by pressing the up and down nm arrows. Fill one cuvette with the blank solution and insert it with the arrow mark directed forward.
Describe the relationship between absorbance and transmittance.
Transmittance is the inverse of absorbance. Absorbance is the light that the solution absorbs, whereas transmittance is the light which passes through a solution.
Describe how absorbance and transmittance are related to the color of an object.
A blue solution does not absorb blue light, it transmits blue light. A green solution does not absorb green light, but transmits green light. So you cannot use red light to measure the absorbance of a solution that is red.
Describe the relationship between absorbance and the concentration of a light-absorbing substance in solution.
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What is the equation represented by CiVi=CfVf?
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Study Notes
Spectrophotometer Use
- Power on the spectrophotometer using the button located at the back.
- The device undergoes a three-minute self-check after turning on.
- Allow 15 minutes for the spectrophotometer to warm up before starting absorbance measurements.
- Ensure the mode is set to absorbance by selecting A/T/C.
- Choose the desired wavelength using up and down arrow buttons for nanometers.
- Prepare a blank solution in a cuvette, directing the arrow mark forward when inserting.
Absorbance vs. Transmittance
- Transmittance is defined as the inverse of absorbance.
- Absorbance refers to the light absorbed by a solution, while transmittance indicates the light that passes through it.
Color Absorbance and Transmittance
- A blue solution transmits blue light rather than absorbing it.
- A green solution transmits green light, indicating similar behavior for colors.
- Red light cannot effectively measure the absorbance of a red solution.
Absorbance and Concentration Relationship
- Higher absorbance correlates with greater amounts of light absorbed by a solution.
- Increased absorbance readings correspond to lower percent transmittance readings on the spectrometer.
CiVi = CfVf
- This equation represents the relationship between initial concentration and volume (CiVi) with final concentration and volume (CfVf) in solutions.
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Description
This quiz focuses on the proper steps needed for using the spectrophotometer effectively. You'll learn about the initial setup, including power-on procedures and settings for measuring absorbance. Perfect for students in laboratory classes that cover photometry and spectroscopy.
