Entropy and the Second Law of Thermodynamics

These flashcards cover key concepts and definitions related to entropy and spontaneity in thermodynamics, aiding in the understanding of the second and third laws of thermodynamics.

Entropy (ΔS)

A measurement of the randomness or disorder of a system.

Second Law of Thermodynamics

In any spontaneous process, the total entropy of the universe increases (ΔSuniv > 0).

Spontaneous Process

A reaction that occurs without continuous intervention.

Nonspontaneous Process

A reaction that requires continuous input of energy to proceed.

Gibbs Free Energy (G)

A thermodynamic potential that indicates spontaneity; defined as G = H - TS.

Exothermic Reaction

A reaction that releases heat, generally preferred for spontaneity.

Endothermic Reaction

A reaction that absorbs heat, less favored for spontaneity.

Third Law of Thermodynamics

The entropy of a perfect crystal approaches zero as temperature approaches absolute zero.

Molar Entropy (S°)

The entropy of one mole of a substance under standard conditions (1 atm, 298 K).

Temperature's Role in Spontaneity

Temperature can determine whether a reaction is spontaneous depending on ΔH and ΔS.

Heat Transfer in Spontaneity

Energy must be discarded as heat to maintain process spontaneity.

Increase in Entropy

Occurs with an increase in temperature, phase changes, or an increase in the number of particles.

State Function

A property dependent only on the current state of a system, not on how it got there.