Two gas-phase reactions occurring at are listed with their standard entropy changes

CHEMISTRY · Multi-part · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

Two gas-phase reactions occurring at 298 K298\,\text{K} are listed with their standard entropy changes. Reaction 1: 2 SO2(g)+O2(g)→2 SO3(g)2\,\text{SO}_2(g) + \text{O}_2(g) \rightarrow 2\,\text{SO}_3(g)  ΔS1∘=−187.9 J mol−1 K−1\Delta S^\circ_{1} = -187.9\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1} Reaction 2: SO3(g)+H2O(l)→H2SO4(l)\text{SO}_3(g) + \text{H}_2\text{O}(l) \rightarrow \text{H}_2\text{SO}_4(l)  ΔS2∘=−145.0 J mol−1 K−1\Delta S^\circ_{2} = -145.0\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1} The following standard molar entropies are tabulated. Substance  S°(298 K298\,\text{K}) SO2(g)\text{SO}_2(g)    248.2 J mol−1 K−1248.2\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1} O2(g)\text{O}_2(g)    205.0 J mol−1 K−1205.0\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1} H2O(l)\text{H}_2\text{O}(l)    69.9 J mol−1 K−169.9\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1} (a) Using Reaction 1, determine the standard molar entropy of SO3(g)\text{SO}_3(g) at 298 K298\,\text{K}. (b) Employ your result from part (a) and the data for Reaction 2 to calculate the standard molar entropy of liquid H2SO4\text{H}_2\text{SO}_4 at 298 K298\,\text{K}. (c) The production of sulfuric acid involves a gas-to-liquid transformation. Analyze how the entropy changes in parts (a) and (b) collectively illustrate the influence of phase changes and molecular complexity on disorder.

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