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- 1. Multiple Choice
You want to measure the absorbance of a DNA sample. What type of spectrophotometer would you use?
UV spectrophotometer
Visible light spectrophotemeter
MRI
Mass spectrometer
- 2. Multiple Choice
Objects appear to be different colors to our eyes because we see:
Light that is reflected by the object
Light that is absorbed by the object
Infrared light
Ultraviolet light
- 3. Multiple Choice
Of the steps listed, which would you do first?
Allow the Spec to warm up per manufacturer's instructions
Wipe the blank cuvette to remove fingerprints
With the cuvette removed, set the absorbance to 0
Insert the blank cuvette and calibrate the spec.
- 4. Multiple Choice
When preparing a blank, how do you choose the correct liquid?
Use the same liquid that is mixed with your substance of interest.
Use ethanol for proteins and water for starches.
Use distilled water whenever possible.
Use methanol whenever it is available.
- 5. Multiple Choice
What is the purpose of creating a standard curve?
It allows you to determine the concentration of an unknown solution.
It allows you to estimate the absorbance of a substance with a known concentration.
It provides you with the entire absorption spectrum of a substance.
It allows you to determine what chemical elements are present in a solution.
- 6. Multiple Choice
If a substance is colored when you observe it, what type of spectrophotometer will you most likely use?
UV spectrophotometer
Visible light spectrophotemeter
MRI
Mass spectrometer
- 7. Multiple Choice
What are some steps to follow when preparing a standard curve?
Measure several samples of known dilution at one specific wavelength and plot their absorbance on a graph vs. concentration. Then add a line of best fit.
Measure two samples of known dilution at one specific wavelength and plot their absorbance on a graph vs. concentration. Then add a line of best fit.
Measure several samples of known dilution at many wavelengths and plot their absorbance on a graph vs. concentration. Then add a line of best fit.
Measure several samples of known dilution and then use a line of best fit to determine their wavelength.
- 8. Multiple Choice
Optimally, where should your unknown concentrations fall in your standard curve?
Close the midpoint between your know concentrations.
To the right of your highest data point.
To the left of your lowest data point.
When possible, above the line of best fit.
- 9. Multiple Choice
A spectrophotometer can be used to (check all that apply):
determine the presence of a substance in a solution.
measure the concentration of an unknown solution.
determine the molecular composition of an unknown substance.
identify an unknown substance
- 10. Multiple Choice
The amount of light absorbed by a sample is called its:
Absorbance
Transmittance
Hue
Saturation
- 11. Multiple Choice
The amount of light that passes through a sample is called:
Transmittance
Absorbance
Radiation
Quantum force
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