Solution

ID: past-exam-of-the-chemistry-a-course-of-the-university-of-cambridge/2024/paper-2/a7/b/iii/solution

The activation enthalpy is obtained from the slope across the measured interval. The activation entropy comes from the intercept at , far outside that interval, so a small slope uncertainty can produce a much larger uncertainty in the extrapolated intercept. Slope and intercept errors are consequently strongly correlated.
The entropy is also sensitive to the assumed prefactor and standard concentration, whereas a constant multiplicative calibration error shifts the intercept without changing the slope. This explains why its inferred precision is often poorer. Since enthalpy and entropy have different units, a claim about which absolute numerical uncertainty is larger requires a stated comparison convention.

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