In this worksheet, we will practice calculating concentrations from UV–vis spectra, using calibration curves or molar extinction coefficients.
Which of the following is a false statement about molar absorptivity coefficients?
- AMolar absorptivity coefficients are calculated based on absorbance and concentration of the solution.
- BMolar absorptivities can be used to compare the ability to absorb light at a given wavelength of different chromophores.
- CMolar absorptivity coefficients for organic molecules are typically M−1⋅cm−1.
- DMolar absorptivities will be the same for each peak, regardless of wavelength, for a given molecule’s UV-Vis spectrum.
The regression line from a plot of absorbance versus concentration yields: . If the absorbance of an unknown is measured to be 0.124, what is the concentration of the analyte?
Fill in the blank. The relationship between the analyte concentration and the intensity of measured radiation from thermal excitation methods, such as a flame or plasma, is .
Fill in the blank. Background correction in flame atomic absorption spectroscopy can minimize the effect of .
- AReactions between the analyte and matrix
- BIonization of the analyte
- CNon-volatilization of the analyte
- DScattering and absorption by the matrix of the analyte