Past exam of the chemistry course of the year 1 of the natural sciences course of the University of Cambridge / 2024 / Paper 1 / 4 / a / iii / Solution

For a first-order reaction with no appreciable reverse contribution in this decay experiment,With fixed path length and attenuation coefficient, and absorbance attributable to ONOO after blank/background correction, the Beer-Lambert law gives $A(t)=\epsilon l{c}_0{e}^{-kt}$. ThereforeThe gradient is $-k$, in ${\mathrm{s}}^{-1}$ when time is measured in seconds. Constant illumination wavelength, homogeneous sampling and negligible product absorbance at that wavelength are required for this direct interpretation.