What does the T in the formula ΔG = ΔH - TΔS signify?

• A. Temperature
• B. Time
• C. Total heat
• D. Both entropy and energy balance

Answer: (A)

In the formula ΔG = ΔH - TΔS, the T specifically denotes temperature, which is measured in Kelvin. This temperature plays a crucial role in determining the spontaneity of a reaction.

The Gibbs free energy change (ΔG) is a thermodynamic potential that indicates whether a reaction will occur spontaneously at constant temperature and pressure. The term ΔH represents the change in enthalpy (or heat content), while ΔS stands for the change in entropy (or the degree of disorder in a system). By multiplying the entropy change (ΔS) by the absolute temperature (T), you quantify how much the entropy change influences the overall energy balance of a reaction at a specific temperature.

If the temperature increases, the contribution of the ΔS term becomes more significant, which can affect the sign and value of ΔG. Thus, T is essential in modulating this energy balance between the enthalpy and entropy factors, ultimately influencing the spontaneity of chemical reactions.