Chemistry

Chemistry

Problem

A research team is designing a three-step synthesis of compound X that must proceed with an overall positive standard entropy change at 298 K298\,\text{K}. The proposed elementary reactions are Step A 2 NO(g)+O2(g)⟶2 NO2(g)2\,\text{NO}(g) + \text{O}_2(g) \longrightarrow 2\,\text{NO}_2(g) Step B NO2(g)⟶NO(g)+12 O2(g)\text{NO}_2(g) \longrightarrow \text{NO}(g) + \frac{1}{2}\,\text{O}_2(g) Step C CO(g)+12 O2(g)⟶CO2(g)\text{CO}(g) + \frac{1}{2}\,\text{O}_2(g) \longrightarrow \text{CO}_2(g) (a) For each step, compute Δngas\Delta n_{\text{gas}}. (b) Using your results from part (a), rank the three steps from most positive to most negative ΔS∘\Delta S^\circ and justify the ranking. (c) The chemists may omit one of the steps without affecting the yield of compound X. Identify which single step should be removed to maximize the overall ΔS∘\Delta S^\circ and explain your reasoning. (d) Suggest one modification (such as changing a stoichiometric coefficient or choosing an alternative intermediate) to any remaining step that would further increase the overall ΔS∘\Delta S^\circ. Justify how your modification achieves this effect without altering the desired product. (a) Calculation of Δngas\Delta n_{\text{gas}} for each step (b) Ranking of steps by ΔS∘\Delta S^\circ with justification (c) Identification and justification of the step to omit (d) Proposed modification to increase overall ΔS∘\Delta S^\circ with justification

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