The accompanying diagram shows how the free energy, G,...

The accompanying diagram shows how the free energy, $G$, changes during a hypothetical reaction $\mathrm{A}(g)+\mathrm{B}(g) \longrightarrow$ $\mathrm{C}(g) .$ On the left are pure reactants, each at $1 \mathrm{~atm},$ and on the right is the pure product, also at 1 atm. (a) What is the significance of the minimum in the plot? (b) What does the quantity $x$, shown on the right side of the diagram, represent? $[$ Section 19.7$]$

The accompanying diagram shows how the free energy, $G$, changes during a hypothetical reaction $\mathrm{A}(g)+\mathrm{B}(g) \longrightarrow$ $\mathrm{C}(g) .$ On the left are pure reactants, each at $1 \mathrm{~atm},$ and on the right is the pure product, also at 1 atm.
(a) What is the significance of the minimum in the plot? (b) What does the quantity $x$, shown on the right side of the diagram, represent? $[$ Section 19.7$]$

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Gibbs Free Energy

Gibbs free energy (G) is the thermodynamic potential that determines the spontaneity of a process at constant temperature and pressure. In a reaction, the change in G indicates whether the system will proceed spontaneously and how energy is redistributed during the process. A free energy diagram plots G along a reaction coordinate, showing the energetic cost and gain as reactants are converted into products.

Reaction Coordinate

The reaction coordinate is an abstract measure of progress along the path from reactants to products. It does not necessarily represent time or distance but rather the extent of molecular reorganization and mixing that takes place during the reaction. The diagram’s horizontal axis is a reaction coordinate that helps visualize how the free energy changes as the reaction proceeds.

Extent of Reaction

The variable x in the diagram represents the extent of the reaction, which is a measure of how far the reaction has advanced from the initial state (pure reactants) toward the final state (pure product). It quantifies the progress of the reaction, often expressed as a fraction or percentage of conversion. In thermodynamics, tracking the extent of reaction is critical for understanding equilibrium and the shifting of free energy.

Transcript

Please give Ace some feedback