An industrial laboratory must determine an accurate value of the standard free energy of dissolution for the non-electrolyte anthracene (C₁₄H₁₀) in ethanol at 298 K. The substance is sparingly soluble, and preliminary calorimetric data are noisy. As the lead chemist, you are asked to design an experimental strategy that delivers ΔG° with an uncertainty of ±0.5 kJ mol⁻¹.
(a) Outline a step-by-step experimental protocol—including specific techniques—for obtaining both the enthalpic and entropic contributions necessary to compute ΔG°. Your protocol must be feasible with standard laboratory equipment.
(b) For each step in part (a), identify the principal source of systematic error and propose a method to minimize that error.
(c) Explain how you would combine the individual measurements to calculate ΔG° and propagate uncertainties to reach the desired ±0.5 kJ mol⁻¹ target.
(d) Anthracene molecules can form π-stacked aggregates in solution. Discuss how neglecting this specific solute–solute interaction could distort the experimentally derived ΔG°, and describe an auxiliary measurement that would reveal whether aggregation is occurring under your experimental conditions.