Absorbance to Molarity Calculator

Formula

The formula to calculate the Molarity (M) is:

\[ M = \frac{A}{\epsilon \cdot l} \]

Where:

\( M \) is the molarity of the solution (M)
\( A \) is the absorbance (unitless)
\( \epsilon \) is the molar absorptivity (L/mol*cm)
\( l \) is the path length (cm)

What is Absorbance?

Absorbance is a measure of the amount of light absorbed by a solution. It is a unitless quantity that is derived from the logarithm of the ratio of incident to transmitted light through a sample. Absorbance is used in various scientific fields, particularly in spectroscopy, to determine the concentration of solutes in a solution.

Example

Let's say the absorbance (A) is 0.5, the molar absorptivity (ε) is 100 L/mol*cm, and the path length (l) is 1 cm. Using the formula:

\[ M = \frac{0.5}{100 \cdot 1} = 0.005 \text{ M} \]

So, the molarity (M) is 0.005 M.