What is the Difference Between Absorptivity and Molar Absorptivity?

There is no significant difference between absorptivity and molar absorptivity, as both terms describe the same concept: the absorbance of a solution per unit path length and concentration. The term "molar absorptivity" is derived from the Beer-Lambert Law, which states that the absorbance of electromagnetic waves by a solution is directly proportional to the concentration of the solution and the path length traveled by the light beam.

Molar absorptivity (ε) is a measure of how strongly a solution can absorb a light beam, and it depends on the type of analyte in the solution. It is calculated using the equation:

$$\varepsilon = \frac{A}{l \times c}$$

where:

• A is the absorbance
• l is the path length (distance traveled by the light beam)
• c is the concentration of the solution

The unit of molar absorptivity is L mol-1 cm-1, as the absorbance is unit-less. In summary, absorptivity and molar absorptivity both describe the absorbance of a solution per unit path length and concentration, with molar absorptivity being a specific term derived from the Beer-Lambert Law.

Comparative Table: Absorptivity vs Molar Absorptivity

There is no significant difference between absorptivity and molar absorptivity, as both terms denote the absorbance of a solution per unit path length and concentration. The term "molar absorptivity" is derived from the Beer-Lambert Law and is used to describe the absorbance of electromagnetic waves by a solution.

Here is a table summarizing the key points:

Both absorptivity and molar absorptivity are used to describe the capacity of a solution to absorb light, with molar absorptivity being a more specific term that takes into account the concentration and path length of the solution.