The change in enthalpy ( ΔHrxn^∘ ) for a reaction is -25.8 kJ / mol. The equilibrium constant f

step 1 In this question we've been given two conditions. Say condition 1 we are at 298 Kelvin and condi

The change in enthalpy ( ΔHrxn^∘ ) for a reaction is -25.8...

The change in enthalpy ( $\Delta H_{\mathrm{rxn}}^{\circ}$ ) for a reaction is $-25.8 \mathrm{~kJ} / \mathrm{mol}$. The equilibrium constant for the reaction is $1.4 \times 10^{3}$ at $298 \mathrm{~K}$. What is the equilibrium constant for the reaction at $655 \mathrm{~K}$ ?

Key Concepts

Reaction Enthalpy

Reaction enthalpy (?H) represents the heat absorbed or released during a reaction at constant pressure. The sign and magnitude of this enthalpy change influence how the equilibrium shifts with temperature changes, as predicted by the van 't Hoff equation. Exothermic reactions, with negative enthalpy changes, typically have decreasing equilibrium constants as temperature increases.

Equilibrium Constant

The equilibrium constant is a measure that quantifies the ratio of concentrations (or partial pressures) of products to reactants at equilibrium under a given set of conditions. It provides insight into the position of equilibrium, indicating whether products or reactants are favored in a reversible reaction.

Temperature Dependence of Equilibrium Constant

The equilibrium constant is inherently dependent on temperature. Changes in temperature can shift the equilibrium position, altering the value of the constant. This dependency often requires adjustments or predictions of the equilibrium state when a reaction system is subjected to different temperature conditions.

Van 't Hoff Equation

The van 't Hoff equation is a fundamental relationship that connects the change in the equilibrium constant with temperature to the reaction's enthalpy change. It is typically expressed in the form ln(K2/K1) = -?H°/R (1/T2 - 1/T1), which allows for the calculation of the equilibrium constant at one temperature given its value at another temperature, assuming that the reaction enthalpy remains constant over the temperature range.

Transcript

Please give Ace some feedback