Question

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.

Answer 1

Answer:

4.36 ppm

Explanation:

First we convert percent transmittance to absorbance:

• A = 2 - log(%T)

• A = 0.268

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

• A = ε*l*C

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.

• 0.268 = 6.14x10⁻²L·ppm⁻¹ * 1.00 cm * C

• C = 4.36 ppm