Question

Assuming linear behavior and a pathlength of exactly 1 cm, what molar concentration will measure an absorbance of

Answer 1

The molar concentration that will measure an absorbance of 1.0 can be calculated using Beer's Law equation: A = ɛcl. For the provided example of NAD*, the concentration is calculated to be 5.6 x 10-5 M.

Step-by-step explanation:

The molar concentration that will measure an absorbance of 1.0, assuming linear behavior and a pathlength of 1 cm, can be calculated using Beer's Law equation. Beer's Law states that the absorbance (A) is equal to the molar absorptivity (ɛ) multiplied by the path length (l) and the concentration (c) of the sample: A = ɛcl.

In the example provided, the molar absorptivity (ɛ) for NAD* at 260 nm is given as 18,000 L* mol ¹*cm-¹. The absorbance (A) is measured as 1.0. By rearranging the equation to solve for concentration (c), we can plug in the known values and calculate the concentration of the sample: c = A / (ɛl).

Substituting the values, we get: c = 1.0 / (18,000 L* mol ¹*cm-¹ * 1 cm) = 5.6 x 10-5 M.

Answer 2

For this problem, we use the equation derived from Beer's Law as written below:

A = ∈LC,
where
A is the absorbance
∈ is the molar absorptivity
L is the path length of the cuvette
C is the concentration of the sample solution placed in the cuvette

To determine C, we have to know the rest of the parameters. Generally, the equation for C would be:

C = A/∈L = A/∈(1 cm)
C = A/∈

If you know the absorbance and the molar absorptivity in mol/L·cm, you can determine the value of C.