Consider the following two reactions and their standard entropy changes

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

Consider the following two reactions and their standard entropy changes. (1) 2 SO2(g)+O2(g)→2 SO3(g)ΔS1∘=−187.9 J mol−1 K−1\displaystyle 2\,\text{SO}_2(g) + \text{O}_2(g) \rightarrow 2\,\text{SO}_3(g) \qquad \Delta S_1^\circ = -187.9\,\text{J\,mol}^{-1}\,\text{K}^{-1} (2) S(s)+O2(g)→SO2(g)ΔS2∘=+248.1 J mol−1 K−1\displaystyle \text{S}(s) + \text{O}_2(g) \rightarrow \text{SO}_2(g) \qquad \Delta S_2^\circ = +248.1\,\text{J\,mol}^{-1}\,\text{K}^{-1} Using ONLY these two reactions, calculate ΔS∘\Delta S^\circ for the formation of sulfur trioxide directly from elemental sulfur: S(s)+32 O2(g)→SO3(g).\displaystyle \text{S}(s) + \tfrac32\,\text{O}_2(g) \rightarrow \text{SO}_3(g). (a) +60.2 J mol−1 K−1+60.2\,\text{J\,mol}^{-1}\,\text{K}^{-1} (b) +342 J mol−1 K−1+342\,\text{J\,mol}^{-1}\,\text{K}^{-1} (c) +154 J mol−1 K−1+154\,\text{J\,mol}^{-1}\,\text{K}^{-1} (d) −154 J mol−1 K−1-154\,\text{J\,mol}^{-1}\,\text{K}^{-1}

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