Define entropy.

1. (a)Define entropy.[1]
2. (b)(i)Fig. 3.1 shows how the entropy, S, of a pure substance changes with temperature, T. [Figure 3.1] Identify the process occurring at each of the temperatures T₁ and T2. T₁ ............................................ T₂ ............................................[1]
3. (b)(ii)Explain why the entropy change, ΔS, at T2 is bigger than the entropy change at T₁.[1]
4. (c)The equation for the reduction of iron(III) oxide by carbon monoxide at 450 °C is shown. Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g) ΔGº = −36.2 kJ mol⁻¹ Table 3.1 shows the enthalpy of formation, ΔHᶠ, and the entropy, Sº, for some substances. [Table 3.1] Use the data in Table 3.1 to calculate the entropy, Sº, of carbon monoxide at 450 °C. Show your working. Sº of CO(g) = ................................. JK⁻¹ mol⁻¹ [3][3]
5. (d)Iron(II) oxide can also be reduced to iron by carbon monoxide, as shown. FeO(s) + CO(g) → Fe(s) + CO2(g) ΔH° = −11.1 kJ mol⁻¹ ΔS° = −15.2 J K⁻¹ mol⁻¹ State the effect of increasing temperature on the feasibility of this reaction. Explain your answer.[2]

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