Chapter 18, Problem 18.92QP

Interpretation Introduction

Interpretation:

For the given reaction, the change in entropy in the system ${\text{(ΔS}}_{\text{sys}})$, change in entropy in the surroundings ${\text{(ΔS}}_{\text{surr}})$ and change in entropy of the universe ${\text{(ΔS}}_{\text{univ}})$ has to be calculated.

Concept Introduction:

Entropy is a thermodynamic quantity, which is the measure of randomness in a system.  The term entropy is useful in explaining the spontaneity of a process.  The second law of thermodynamics says that entropy of the universe is increasing.  The change in entropy in the universe ${\text{(ΔS}}_{\text{univ}})$ is given by the summation of entropy change in the system ${\text{(ΔS}}_{\text{sys}})$ and surroundings ${\text{(ΔS}}_{\text{surr}})$.

${\text{ΔS}}_{\text{univ}}{\text{=ΔS}}_{\text{sys}}{\text{+ΔS}}_{\text{surr}}$

${\text{ΔS}}_{\text{sys}}$ can be found by the following equation.

${\text{ΔS}}_{\text{sys}}{\text{= ΔS}}_{\text{products}}{\text{- ΔS}}_{\text{reactants}}$

${\text{ΔS}}_{\text{surr}}$ associated with reaction can be found by the following equation.

${\text{ΔS}}_{\text{surr}}\text{=}\frac{{\text{-ΔΗ}}_{\text{sys}}}{\text{T}}$

Where,

  ${\text{ΔΗ}}_{\text{sys}}$ is the change in enthalpy of the system

  $\text{T}$ is the absolute value of the temperature