Here are the essential concepts you must grasp in order to answer the question correctly.
Gibbs Free Energy (ΔG)
Gibbs Free Energy (ΔG) is a thermodynamic potential that measures the maximum reversible work obtainable from a thermodynamic system at constant temperature and pressure. It is a crucial concept in predicting the spontaneity of a reaction; a negative ΔG indicates a spontaneous process, while a positive ΔG suggests non-spontaneity. The standard Gibbs free energy change (ΔG°) is calculated under standard conditions, providing a reference point for reactions.
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Sublimation
Sublimation is the phase transition in which a substance changes directly from a solid to a gas without passing through the liquid phase. This process occurs when the molecules in the solid gain enough energy to overcome intermolecular forces and enter the gaseous state. Understanding sublimation is essential for calculating the Gibbs free energy change for the reaction involving iodine, as it directly relates to the enthalpy and entropy changes during the phase transition.
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Standard State Conditions
Standard state conditions refer to a set of specific conditions (usually 1 bar of pressure and a specified temperature, often 25 °C) under which thermodynamic measurements are made. These conditions allow for the comparison of thermodynamic data across different substances. When calculating ΔG°rxn, it is important to use standard state values for enthalpy (ΔH°) and entropy (ΔS°) to ensure accurate results for the reaction at the specified temperature.
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