Define Spectrophotometry.
Technique for measuring a substance's light absorption to determine its concentration.
What is a monochromator?
Part of a spectrophotometer that selects a specific wavelength of light.
Define absorbance (A).
The measure of a substance's capacity to absorb light of a specified wavelength.
What is molar absorptivity (\(\varepsilon\))?
A measure of how strongly a chemical species absorbs light at a given wavelength (L/mol·cm).
Define path length (b).
The distance the light travels through the sample, usually the width of the cuvette (cm).
Define complementary colors.
Colors opposite each other on the color wheel; a substance absorbs its complementary color most strongly.
What is the difference between absorbance and transmittance?
Absorbance: amount of light absorbed by the sample. Transmittance: amount of light that passes through the sample.
What is the effect of increasing the concentration of a solution on its absorbance (assuming constant path length)?
The absorbance increases proportionally.
What happens if the wrong wavelength of light is used in spectrophotometry?
The absorbance measurement will be inaccurate, leading to an incorrect concentration determination.
What is the effect of using a cuvette with a longer path length?
The absorbance increases proportionally, according to Beer-Lambert Law.
