Fructose 6-phosphate (Fru-6-P) breaks down in water as shown below with ΔG° = −15 kJ/mol.Fru-6-P + H₂O → fructose + P_iIn evaluating the equilibrium concentrations of each species, which expression gives the molar concentration of fructose if [Fru-6-P] = x mol/L and [P_i] = 1.0 mol/L? (Note: Use RT = 2.5 kJ/mol.)

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11ecba4b_cdb5_7ea1_99fe_adf8cd93b687_MD0008_00 The equilibrium constant K_eq for a reaction is expressed as a ratio of the molar concentrations of the products over the reactants, each raised to the power of its respective balanced reaction coefficient (in a hydrolysis reaction, water is the solvent and is omitted). The K_eq is related to the standard Gibbs free energy ΔG° of the reaction by the relationship 11ecba4b_f673_a3d2_99fe_a7eb0d970806_MD0008_11 where R is the gas constant and T is the absolute temperature. Solving this equation for K_eq and substituting the equivalent concentration ratio for the K_eq of the hydrolysis of fructose 6-phosphate (Fru-6-P) into the equation relates the concentrations of Fru-6-P, fructose, and inorganic orthophosphate (P_i) to ΔG° as 11ecba4c_16f0_9873_99fe_8b7be1ee9782_MD0008_11 Finally, solving for [fructose] and substituting the given values for [Fru-6-P], [P_i], and RT into the equation yields 11ecba4c_3662_acc5_99fe_ddfa37ab6983_MD0008_11 Therefore, the expression for the molar concentration of fructose at equilibrium is xe⁶. (Choice A) Both the leading coefficient and the sign of the exponent are incorrect. This error results from using an inverted K_eq ratio in the calculation setup and from algebra errors that give an inverted [Fru-6-P]/[P_i] ratio. (Choice B) The sign of the exponent is incorrect. This error can be obtained from failing to cancel the negative signs in the −ΔG° term during the calculation or from using an inverted K_eq ratio in the calculation. (Choice C) The leading coefficient of the term is incorrect. This error could result from algebra errors that give an inverted [Fru-6-P]/[P_i] ratio when solving for [fructose]. Educational objective: The equilibrium constant Keq for a reaction is expressed as a ratio of the molar concentrations of the products over the reactants, each raised to the power of its respective balanced reaction coefficients. The standard Gibbs free energy ΔG° and the Keq are related via the gas constant R and absolute temperature T by the equation ΔG° = −RT ln Keq.

Fructose 6-Phosphate (Fru-6-P) Breaks Down in Water as Shown Below