A reaction A+B →C+D is exothermic and produces a positive...

A reaction $A+B \rightarrow C+D$ is exothermic and produces a positive entropy change. Is such a reaction (i) possible at high temperature, (ii) possible only at low temperature, (iii) not possible at any temperature, or (iv) possible at any temperature?

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 is a thermodynamic potential defined by ?G = ?H - T?S. It predicts the spontaneity of a reaction by considering both the enthalpy change and the entropy change. A negative ?G indicates that the reaction is spontaneous under the given conditions.

Exothermic Reaction

An exothermic reaction is one in which heat is released into the surroundings, meaning the enthalpy change (?H) is negative. This release of energy contributes to making the reaction more favorable.

Entropy Change

Entropy is a measure of disorder or randomness in a system. A positive entropy change (?S > 0) signifies that the products are more disordered than the reactants. This increase in disorder tends to make the reaction spontaneous, especially at higher temperatures.

Temperature Dependence in Reaction Spontaneity

The spontaneity of a reaction depends on the balance between enthalpy and entropy changes as expressed in the Gibbs free energy equation. For reactions with a negative ?H and a positive ?S, the term -T?S further lowers ?G, ensuring that the reaction is spontaneous at all temperatures. This means the reaction is thermodynamically favored regardless of temperature.

Transcript

Please give Ace some feedback