At , hydrogen iodide gas can decompose according to the balanced equation . Under…

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

Problem

At 298 K298\,\text{K}, hydrogen iodide gas can decompose according to the balanced equation 2 HI(g)⇌H2(g)+I2(g)2\,\text{HI}(g) \rightleftharpoons \text{H}_2(g) + \text{I}_2(g). Under standard-state conditions at this temperature, the equilibrium constant for the reaction is 2.1×10−22.1 \times 10^{-2}. The universal gas constant may be taken as R=8.314 J mol−1 K−1R = 8.314\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1}. (a) Calculate the standard Gibbs free energy change, ΔG∘\Delta G^\circ, for the reaction as written at 298 K298\,\text{K}. Express your answer in kJ mol−1\text{kJ}\,\text{mol}^{-1} and include the correct sign. (b) Based on your calculated value of ΔG∘\Delta G^\circ, discuss whether the reaction is thermodynamically favorable and identify which side of the equilibrium (reactants or products) is favored under standard-state conditions.

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