Intermediate Topic 474 of 1102 Kinetics & Equilibrium
Effect of Temperature on Equilibrium
Raising temperature favours the endothermic direction and changes K.
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In-depth explanation of Effect of Temperature on Equilibrium
Temperature is the only condition that changes the numerical value of the equilibrium constant. Raising the temperature favours the endothermic direction, because heat is effectively a reactant in that direction, and lowering the temperature favours the exothermic direction. The van't Hoff equation describes the quantitative dependence: ln(K2/K1) = -(delta H/R)(1/T2 - 1/T1), where delta H is the standard enthalpy change. This relation shows that K increases with temperature for endothermic reactions and decreases for exothermic reactions. Temperature effects are central to choosing conditions in industrial syntheses, where yield and reaction rate must be balanced.
Going deeper: Effect of Temperature on Equilibrium
Key ideas: Direction rule: treat heat as a reactant for endothermic reactions and as a product for exothermic ones. Quantitatively, d ln K/dT = delta H standard / (R T^2), so a larger magnitude of delta H gives a larger change in K. For delta H of +50 kJ per mol, raising temperature from 300 K to 310 K raises K by about 1.9 times.
Common mistakes and connections: Students say that heating always shifts a reaction forward, or ignore that K itself changes. Another error is confusing the rate effect with the equilibrium effect: raising temperature speeds both directions, but shifts the position only toward the endothermic direction. The sign conventions for delta H also cause errors. Industrial processes like Haber show the compromise between yield and rate.
Visualization of Effect of Temperature on Equilibrium
For endothermic N2O4 to 2NO2 (delta H about +57 kJ/mol), ln K rises with T, so heating makes more brown NO2. The interactive lesson shows this as a live animation or chart.
Worked example and use case
The brown gas NO2 is favoured at high temperature over colourless N2O4, because the dissociation of N2O4 is endothermic.
Frequently asked questions about Effect of Temperature on Equilibrium
What is Effect of Temperature on Equilibrium?
Raising temperature favours the endothermic direction and changes K.
Is Effect of Temperature on Equilibrium a beginner, intermediate or advanced topic?
Effect of Temperature on Equilibrium is a intermediate topic in Kinetics & Equilibrium. It builds on the vocabulary of beginner topics in this area.
What should I learn before Effect of Temperature on Equilibrium?
Study these earlier topics in Kinetics & Equilibrium first: Le Chatelier's Principle, Effect of Concentration on Equilibrium, Effect of Pressure on Equilibrium.
What comes after Effect of Temperature on Equilibrium?
The next topics in Kinetics & Equilibrium are Effect of Catalyst on Equilibrium and Haber Process.
Can I practise Effect of Temperature on Equilibrium with quizzes?
Yes. The interactive lesson includes a self-check question on Effect of Temperature on Equilibrium, and the Kinetics & Equilibrium quiz draws on every topic in this area.
Where Effect of Temperature on Equilibrium fits in Kinetics & Equilibrium
Effect of Temperature on Equilibrium is topic 55 of 91 in Kinetics & Equilibrium.