Chapter 23, Problem 23.22P

Interpretation Introduction

Interpretation:

Value of $\Delta S_{rxn}^o$ and $\Delta G_{rxn}^o$ has to be calculated for the reaction $\text{C}\left(s,\text{ graphite}\right)+{\text{ CO}}_2\left(g\right)\underset{}{\rightleftharpoons }2\text{ CO}\left(g\right)$. The direction in which the reaction is spontaneous has to be indicated.

Concept Introduction:

Entropy$\left(S\right)$: it is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state.

Value of $\Delta S_{rxn}^o$ can be calculated by the equation:

  $\Delta S_{rxn}^o\text{= }S°\left[\text{products}\right]-S°\left[\text{reactants}\right]$

The Gibbs free energy or the free energy change is a thermodynamic quantity represented by $\Delta G$. Value of $\Delta G_{rxn}^o$ is determined as follows,

  $\Delta G_{rxn}^o=\Delta H_{rxn}^o-T\Delta S_{rxn}^o$

The formula of ${\text{ΔG}}_{\text{rxn}}$ in terms of thermodynamic reaction quotient (Q),

    ${\text{ΔG}}_{rxn}={\text{ΔG}}_{rxn}^o+\text{RT}\text{ln Q}$

If $\Delta G_{rxn}<0$ then the reaction is spontanous in forward reaction and so the reaction will favor products.

If $\Delta G_{rxn}>0$ then the reaction is spontanous in backward reaction and so the reaction will favor reactants.

If $\Delta G_{rxn}=0$ then the reaction is at equilibrium.