Question

A specific steroid has a λmax of 257 nm and a molar absorptivity ε of 11 , 500 L mol − 1 cm − 1 . What is the concentration of the compound in a solution whose absorbance at 257 nm is A = 0.090 with a sample pathlength of 1.00 cm ?

Answer 1

Answer:

$7.83\times 10^{-6} M$ is the concentration of the compound in a solution.

Explanation:

Using Beer-Lambert's law :

Formula used :

$A=\epsilon \times C\times l$

Where:

A = absorbance of solution

C = concentration of solution

l = path length

$\epsilon$ = molar absorptivity coefficient

We have:

C = ? , l = 1.00 cm, A = 0.090

$\epsilon = 11,500 L/(mol cm)$

$C=\frac{A}{\epsilon l}=\frac{0.090}{11,500 L/(mol cm)\times 1.00 cm}$

$C=7.83\times 10^{-6} M$

$7.83\times 10^{-6} M$ is the concentration of the compound in a solution.