Chemistry absorbance

Question

What is the absorbance that corresponds to 45.0 %T? When the concentration of a solution is doubled, the absorbance is also doubled. If a 0.0100 M solution exhibits 45.0 % T at a given wavelength, what will be the %T for a 0.0200 M solution of the same substance?

Answer 1

The formula for absorbance from %T is A = log 100/%T = log 100/45 = 0.347.

Beers law states that absorbance to proportional to the path length and concentration or A = k x l x c. If k and l are constant, the absorbance will double if the concentration doubles, so the absorbance for the 0.0200 solution is 2 x 0.347 = 0.694.