A least-squares analysis of calibration data collected in a 1.00 cm cuvette yields with

CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures

Problem

A least-squares analysis of calibration data collected in a 1.00 cm cuvette yields A=(1.12±0.04)×104cA=(1.12\pm0.04)\times10^{4}c with R2=0.998R^{2}=0.998. Literature reports ε=1.10×104  L mol−1 cm−1\varepsilon=1.10\times10^{4}\;\text{L\,mol}^{-1}\,\text{cm}^{-1} at the same wavelength. Which conclusion is most strongly supported by these results? (a) The discrepancy between experimental and literature values is best explained by a systematic error in the cuvette path length, which made the effective path longer than 1.00 cm1.00\,\text{cm}. (b) The data set is unreliable; an R2R^{2} below 0.9990.999 is insufficient to validate the molar absorptivity. (c) The experimental value of molar absorptivity agrees with the literature value within the stated uncertainty. (d) The 200 L mol−1 cm−1200\,\text{L\,mol}^{-1}\,\text{cm}^{-1} difference between the two values greatly exceeds the stated ±0.04\pm0.04 uncertainty, so the disagreement is statistically significant.

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