A student records absorbance data for a dilute dye solution at its and then repeats…
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A student records absorbance data for a dilute dye solution at its λmax and then repeats the measurement 20 nm away from λmax while keeping path length and concentration constant. Which statement most accurately predicts how the second reading will compare with the first?
(a) The absorbance will decrease but the percent relative error in calculated concentration will stay approximately the same because the Beer–Lambert relationship remains linear at any wavelength.
(b) Both absorbance and percent relative error will remain essentially unchanged because concentration is constant.
(c) The absorbance will decrease and the percent relative error in calculated concentration will increase because molar absorptivity is smaller away from λmax.
(d) The absorbance will increase and the percent relative error in calculated concentration will decrease because stray-light effects are reduced off-peak.