CAIE A-Level Chemistry A2 23.3.3 The Entropy Change for a Reaction S Topic Practice

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Question 1

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Potassium iodide, KI, is used as a reagent in both inorganic and organic chemistry.

KI slowly oxidises in air, forming I2\mathrm{I}_{2}.

reaction 14KI(s)+2CO2( g)+O2( g)→2 K2CO3( s)+2I2( s)ΔH⊖=−203.4 kJ mol−11 \quad 4 \mathrm{KI}(\mathrm{s})+2 \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{~K}_{2} \mathrm{CO}_{3}(\mathrm{~s})+2 \mathrm{I}_{2}(\mathrm{~s}) \quad \Delta H^{\ominus}=-203.4 \mathrm{~kJ} \mathrm{~mol}^{-1}

Table 1.2 shows some data relevant to this question.

Table 1.2

Table 1.2

Calculate the standard entropy change, ΔS⊖\Delta S^{\ominus}, of reaction 1 .

ΔS⊖=…………………………………..JK−1 mol−1\Delta S^{\ominus}=\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots . . \mathrm{JK}^{-1} \mathrm{~mol}^{-1}
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