Entropy, Free Energy & Spontaneity

These flashcards cover key terms and concepts related to entropy, free energy, and spontaneity as outlined in the lecture notes.

Spontaneous Process

A process that occurs on its own without any continuous external influence.

Entropy (S)

A measure of molecular randomness or disorder in a system.

Gibbs Free Energy (ΔG)

Determines whether a chemical or physical process will occur spontaneously, taking into account both enthalpy and entropy.

Positive ΔS

Indicates an increase in randomness or disorder in the system.

Negative ΔS

Indicates that the system becomes more ordered.

Third Law of Thermodynamics

The entropy of a perfectly ordered crystalline substance at absolute zero (0K) is zero.

Standard Molar Entropy (S°)

The entropy of 1 mol of a pure substance at 1 atm and 25°C.

Phase Change

A transition of matter from one state to another, often associated with a significant change in entropy.

Endothermic Process

A process that absorbs heat from the surroundings, typically resulting in a positive change in enthalpy (ΔH).

Exothermic Process

A process that releases heat to the surroundings, typically resulting in a negative change in enthalpy (ΔH).

Spontaneity Conditions

Conditions where ΔH is negative and ΔS is positive lead to spontaneous processes.

Entropy Change (ΔS)

The change in entropy during a process, calculated as Sfinal minus Sinitial.