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Ch.19 - Free Energy & Thermodynamics
Chapter 19, Problem 77a

Use data from Appendix IIB to calculate the equilibrium constants at 25 °C for each reaction. a. 2 CO(g) + O2(g) ⇌ 2 CO2(g)

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Identify the reaction for which you need to calculate the equilibrium constant: 2 CO(g) + O_2(g) ⇌ 2 CO_2(g).
Use the standard Gibbs free energy change (ΔG°) for the reaction to find the equilibrium constant (K) using the relation: ΔG° = -RT ln(K).
Look up the standard Gibbs free energy of formation (ΔG_f°) for each species involved in the reaction from Appendix IIB.
Calculate the ΔG° for the reaction using the formula: ΔG° = Σ(ΔG_f° of products) - Σ(ΔG_f° of reactants).
Substitute the calculated ΔG° and the given temperature (25 °C, which is 298 K) into the equation ΔG° = -RT ln(K) to solve for the equilibrium constant K.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Equilibrium Constant (K)

The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. It is calculated using the formula K = [products]^[coefficients] / [reactants]^[coefficients]. A large K value indicates that products are favored at equilibrium, while a small K value suggests that reactants are favored.
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Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust itself to counteract the change and restore a new equilibrium. This principle helps predict how changes in concentration, pressure, or temperature will affect the position of equilibrium in a chemical reaction.
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Standard Conditions

Standard conditions refer to a set of specific conditions (usually 1 atm pressure and 25 °C) under which thermodynamic measurements are made. These conditions are important for calculating equilibrium constants, as they provide a consistent reference point, allowing for the comparison of K values across different reactions and ensuring that the data used is reliable.
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