Question

Under certain condition for the reaction A - B AH = 17.2 kJ and AS = 22 J/K. At what temperature in K is the reaction at equilibrium? Hint given in feedback.

Answer 1

Answer:

Step 1: Explanation

Gibbs free energy is defined as the amount of energy available for a system to do a work in a thermodynamic condition.

The Gibbs free energy equation is given as

ΔG = ΔH - TΔS

where,

T = Temperature ( in Kelvin)

ΔH = Enthalpy Change

ΔS = Entropy Change

if ΔG < 0 , then the reaction will be spontaneous

if ΔG < 0 , then the reaction will be non-spontaneous

if ΔG = 0 , then the reaction will be at equilibrium

Step 2: Calculation

Given,

T = we need to calculate

ΔH = 17.2 kJ = 17200 J [ note: 1 kJ = 1000 J ]

ΔS = 22 J/K

Since for the reaction to be at equilibrium

ΔG = 0

so, the equation become

ΔG = ΔH - TΔS

=> 0 = ΔH - TΔS

=> T =  ΔH / ΔS

on substituting the given value

T = 17200 J / 22 J/K

=> T = 781.8 K

Hence, the reaction will be equilibrium at 781.8 K