S

Spontaneous Process

ΔG < 0
Quick Reference
Formula / NotationΔG < 0
Also Known AsSpontaneous reaction, thermodynamically favorable, exergonic reaction (ΔG<0), natural process

What is Spontaneous Process?

A spontaneous process is a process that occurs naturally without continuous external intervention under a given set of conditions. Spontaneity is governed by the Gibbs free energy: ΔG < 0 for spontaneous processes at constant T and P. A spontaneous process is not necessarily fast — diamond converting to graphite is thermodynamically spontaneous but kinetically very slow. Spontaneity depends on temperature, pressure, and concentrations.

Formula & Notation

ΔG < 0

Other Names / Synonyms: Spontaneous reaction, thermodynamically favorable, exergonic reaction (ΔG<0), natural process

Properties & Characteristics

ΔG = ΔH − TΔS. Spontaneous: ΔG < 0. Non-spontaneous: ΔG > 0. Equilibrium: ΔG = 0. Temperature effect: ΔG = ΔH − TΔS. Always spontaneous: ΔH < 0 and ΔS > 0. Never spontaneous: ΔH > 0 and ΔS < 0. Temperature dependent: ΔH and ΔS same sign. Second Law: entropy of universe increases for spontaneous processes.

Uses & Applications

Predicting reaction direction. Determining equilibrium conditions. Understanding why reactions proceed. Electrochemical cell spontaneity. Biological energy coupling (ATP hydrolysis drives non-spontaneous reactions). Industrial process feasibility assessment.

Safety Information

Conceptual classification — no direct safety concerns. Some spontaneous reactions are highly exothermic and potentially hazardous (combustion, acid-metal reactions). Thermodynamic spontaneity does not imply safe!

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Spontaneous Process
Formula ΔG < 0
Synonyms Spontaneous reaction, thermodynamically favorable, exergonic reaction (ΔG<0), natural process

Frequently Asked Questions

A spontaneous process is a process that occurs naturally without continuous external intervention under a given set of conditions. Spontaneity is governed by the Gibbs free energy: ΔG < 0 for spontaneous processes at constant T and P. A spontaneous process is not necessarily fast — diamond converting to graphite is thermodynamically spontaneous but kinetically very slow. Spontaneity depends on temperature, pressure, and concentrations.

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