posted by Leslie .
The rate of a first-order reaction is followed by spectroscopy, monitoring the absorption of a colored reactant at 520 nm . The reaction occurs in a 1.29-cm sample cell, and the only colored species in the reaction has an extinction coefficient of 5700 cm-1M-1 at 520 nm .
a) Calculate the initial concentration of the colored reactant if the absorbance is 0.564 at the beginning of the reaction.
b) The absorbance falls to 0.254 at 30.0 min . Calculate the rate constant in units of s-1.
c) Calculate the half-life of the reaction. (in sec)
d) How long does it take for the absorbance to fall to 0.104? (in sec)
See your post below.