The complex [FeSCN]2+ has an absorptivity of 6.14×10−2 L/(mg⋅cm) at a wavelength of 580 nm. The transmittance of a solution sample was measured in a 1.00 cm cell, and the percent transmittance %T was 53.9%. Calculate the concentration of the solution in ppm.

4.36 ppm

Explanation:

First we convert percent transmittance to absorbance:

Then we calculate the concentration of the solution, using Lambert-Beer's equation:

It is usually used with molar concentrations but given that the given absortivity is in ppm terms and the answer is also in ppm, we can simply use the given value.

it is the most commonly accepted one