Question

An unknown solution of triiodide registers an absorbance of 0.782 at 362 nm. A series of triiodide solutions of known concentration were analyzed at this wavelength and a standard curve was created. The equation of the best fit line from the standard curve was determined to be A = (3.2 x 10^-1 M^-1)c, where A= absorbance and c is the concentration of the solution. The constant value in this equation is the value of el. What is the concentration of the triiodide in the unknown solution? Help I wasn't sure how to start this.

Answer 1

The Beer-Lambert equation can be expressed as A=abc => c= A/a
were
A= absorbance
a= molar absortivity
b= optic pass =1cm, allways the same doesnt affect the calculations just it is nice to keep in the formula to make it easy to remember "abc"
c= the concentration of the substance

The problem tells you that the value for "a" has been calculated = 3.2 x 10^-1 M^-1

Then you have to replace the value of A= 0.782 and isolate c from Beer Lambert equation and you will have your problem solved!!

Answer 2

thank you.