Question

Consider the reaction a + b c +

d. at biochemical equilibrium (25°c, ph of 7), the concentration of a is 0.2 m, the concentration of b is 0.2 m, the concentration of c is 0.8 m, and the concentration of d is 0.8 m. calculate δg and δg° ′ under these conditions.

Answer 1

when the reaction is at equilibrium ∴ΔG = Zero
now we need to get Δ G°, we can get it from this formula:
ΔG° = - RT㏑K(eq)
when we have R = 8.315 J/mol°K and T in Kelvin = 25+273 = 298
so we need to get the K(eq) from this formula:
K(eq) = concentration of products / concentration of reactants
= [ C] [ D] / [A] [B]
= (0.8*0.8) / (0.2*0.2) = 16
by substitution in ΔG° formula:
∴ ΔG° = - 8.315 * 298 *㏑(16) = -6870 Jmol^-1 /1000 = - 6.87 KJ mol^-1