The APsolute RecAP: Chemistry Edition - Episode 53: Beer-Lambert Law
Description
Coffee needs to be “just right” and we can tell how strong it is by the color (0:30 ). We can use the color to determine concentration also in Chemistry (1:09 ). The color we see is determined by the wavelength an object reflects, while absorbing all other colors (1:23 ).
The Beer-Lambert Law absorbance to molar absorptivity, path length and concentration (2:08 ). In AP Chemistry, the molar absorptivity and path length are held constant, therefore absorbance is directly proportional to concentration (2:28 ).
Experimentally, we measure absorbance using spectrophotometers (4:41 ). To determine the concentration of, for example, blue dye in a sports drink, we have to create a calibration curve using solutions with known concentration and measuring the absorbance (5:35 ). We can then use the graph and a measurement of absorbance of the sports drink to determine the concentration (6:16 ).
In which of the following examples could you use spectroscopy and the Beer-Lambert law to determine the concentration?
A. Determination of bilirubin in blood plasma samples. B. Determination of colorless zinc(II) nitrate in a sample. C. Determination of ethanol (drinking alcohol) in an alcoholic beverage. D. Determination of isopropyl in hand sanitizer.
Thank you for listening to The APsolute RecAP: Chemistry Edition!
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