The standard free energy of formation of gaseous hydrogen iodide is 1.30 kJ/mol at 25°C.Find K_p for the reaction H₂(g)+ I₂(s) 2HI(g)at this temperature. A)7.0 B)7100 C)1.0 D)2.4 E)2.9

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Quizplus · Accepted Answer

We can use the equation: ΔG° = -RTln(K) where ΔG° is the standard free energy change, R is the gas constant, T is the temperature in Kelvin, and K is the equilibrium constant. Plugging in the values: ΔG° = 1.30 kJ/mol R = 8.314 J/(mol K) T = 298 K We convert ΔG° to Joules per mole: ΔG° = 1300 J/mol Substituting: 1300 J/mol = -8.314 J/(mol K) * 298 K * ln(K) Simplifying: ln(K) = -1.754 K = e^-1.754 K = 0.173 Finally, we need to square K (because of the stoichiometry of the balanced equation): K^2 = 0.030 Therefore, K_p = 2.9 (rounded to one decimal place), which corresponds to answer choice (E).

The Standard Free Energy of Formation of Gaseous Hydrogen Iodide