Q20.67 P - Chemistry: Molecular Nature Of Matter And Change

Question

What is the difference between ${\mathbf{\text{ΔG}}}^{\mathbf{\text{°}}}$ and $\mathbf{\text{ΔG}}$ ? Under what circumstances does  ${\mathbf{\text{ΔG=ΔG}}}^{\mathbf{\text{°}}}$?

Step-by-Step Solution

Answer

${\text{ΔG}}^{\text{o}}=\text{ΔG}$  when all concentrations equal 1M and all partial pressures equal 1 atm.

This is due to the fact that the values of  Q=1 and  $\text{lnQ=0}$ in the following equation,

 ${\text{ΔG=ΔG}}^{\text{o}}\text{+RTln(Q)}$

Where,

R is gas constant

T  is the temperature

$\text{ΔG}$  is the free energy

Step 1: Definition of Concept

Solubility: The maximum amount of solute that can be dissolved in the solvent at equilibrium is defined as solubility.

Constant of soluble product: For equilibrium between solids and their respective ions in a solution, the solubility product constant is defined. In general, the term "solubility product" refers to water-equilibrium insoluble or slightly soluble ionic substances.

Step 2: Find the difference between ΔG ° and ΔG

Considering the given information:

When all of the system's components are in their standard states, the standard free energy change  ${\text{ΔG}}^{\text{o}}$ occurs.

The standard state is defined as $\text{1 atm}$  for gases, 1M for solutes, and 1M for pure solids and liquids. The term "standard state" does not specify a temperature because it can occur at any temperature.

 ${\text{ΔG}}^{\text{o}}=\text{ΔG}$ when all concentrations equal 1M and all partial pressures equal 1 atm.

This is due to the fact that the values of Q=1 and  $\text{lnQ=0}$ in the following equation,

 ${\text{ΔG=ΔG}}^{\text{o}}\text{+RTln(Q)}$

Where,

R is gas constant

T  is the temperature

  $\text{ΔG}$is the free energy

${\mathbf{\text{ΔG}}}^{\mathbf{\text{o}}}$ is standard free energy.