Question

pre - lab 7 question 3 4.75 points
using a cuvette with a path length of 1.00 cm you record an absorbance of 0.150 at a given wavelength for a sample with a concentration of 0.0600 m. please calculate the molar absorptivity at this wavelength.
a 0.400 m⁻¹·cm⁻¹
b 0.090 m⁻¹·cm⁻¹
c 0.79 m⁻¹·cm⁻¹
d 2.50 m⁻¹·cm⁻¹

Explanation:

Step1: Recall Beer - Lambert Law

The Beer - Lambert Law is \(A=\epsilon lc\), where \(A\) is absorbance, \(\epsilon\) is molar absorptivity, \(l\) is path length, and \(c\) is concentration. We need to solve for \(\epsilon\), so \(\epsilon=\frac{A}{lc}\).

Step2: Substitute values

Given \(A = 0.150\), \(l=1.00\ cm\), and \(c = 0.0600\ M\).
Substitute into the formula: \(\epsilon=\frac{0.150}{1.00\times0.0600}\).

Step3: Calculate

\(\epsilon=\frac{0.150}{0.0600}= 2.50\ M^{-1}\cdot cm^{-1}\)

Answer:

D. \(2.50\ M^{-1}\cdot cm^{-1}\)