A 3.7 × 10⁻⁴ M solution of compound X has an absorbance of 0.5342 when measured at 740 nm.Assuming a pathlength of 1 cm,calculate compound X's molar absorptivity. A)1443 M⁻¹ cm⁻¹ B)9)926 × 10⁵ M⁻¹ cm⁻¹ C)5059 M⁻¹ cm⁻¹ D)735.9 M⁻¹ cm⁻¹ E)1)44 × 10⁵ M⁻¹ cm⁻¹

Question

Quizplus · Accepted Answer

The molar absorptivity (ε) can be calculated using Beer-Lambert Law: A = εlc, where A is absorbance, ε is molar absorptivity, l is path length in cm, and c is concentration in M. Given A = 0.5342, l = 1 cm, and c = 3.7 × 10^-3 M, solving for ε gives ε = A / (lc) = 0.5342 / (1 cm × 3.7 × 10^-3 M) = 144.378 M^-1 cm^-1, which rounds to 1443 M^-1 cm^-1, matching choice A.

A 37 × 10−4 M Solution of Compound X Has an an Absorbance

A 37 × 10⁻⁴ M Solution of Compound X Has an an Absorbance