What is the significance of the temperature (T) in the equation Δ_rG® = Δ_rH® − TΔ_rS®?

In the equation Δ_rG® = Δ_rH® − TΔ_rS®, temperature (T) plays a crucial role in determining the relationship between the change in Gibbs free energy (Δ_rG®), the change in enthalpy (Δ_rH®), and the change in entropy (Δ_rS®) of a reaction. Specifically, the temperature is key to understanding how entropy changes can influence the spontaneity of a reaction.

At higher temperatures, the term TΔ_rS® becomes more significant. If Δ_rS® is positive, increases in temperature can lead to a more negative Δ_rG®, indicating that the reaction becomes more spontaneous. Conversely, if Δ_rS® is negative, higher temperatures can make Δ_rG® less favorable, which could prevent the reaction from occurring spontaneously.

Thus, temperature is not just a constant; it actively participates in the thermodynamic balance that determines whether a reaction will occur under given conditions. This interaction highlights the significance of T in the thermodynamic framework, directly affecting the spontaneity and direction of chemical reactions.