A research team is designing a three-step synthesis of compound X that must proceed…

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

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\,\text{K}

. The proposed elementary reactions are Step A

2\,\text{NO}(g) + \text{O}_2(g) \longrightarrow 2\,\text{NO}_2(g)

Step B

\text{NO}_2(g) \longrightarrow \text{NO}(g) + \frac{1}{2}\,\text{O}_2(g)

Step C

\text{CO}(g) + \frac{1}{2}\,\text{O}_2(g) \longrightarrow \text{CO}_2(g)

(a) Calculation of

\Delta n_{\text{gas}}

for each step (b) Ranking of steps by

\Delta S^\circ

with justification (c) Identification and justification of the step to omit (d) Proposed modification to increase overall

\Delta S^\circ

with justification