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Le Chatelier principle

Le Chatelier principle

6.8
A rule that says a balanced chemical system shifts to undo a change and move back toward balance
  • noun
  • /lə ʃɑːˈteɪliər ˈprɪnsəpəl/
  • Specialized
translation icon : principio de Le Chatelier
  • The chemist explained that when pressure is increased in a gaseous reaction, Le Chatelier's principle indicates that the system will shift to reduce the pressure.

Examples

  • And this is, this is Le Chatelier that you've already know Le Chatelier's principle for pressure.

  • But now some of that is going to react because I, as I just said, Le Chatelier's principle tells me that now there's it's got to counter that.

  • According to Le Chatelier's principle, increasing the temperature of a reaction at equilibrium will shift the reaction to the left to absorb the added heat.

  • In every chemistry class, students learn about Le Chatelier's principle and how it helps predict the effects of changes on reaction equilibrium.

Synonyms

Le Chatelier's principle
vsLe Chatelier principle
  • Specialized
7.4

A chemistry rule saying a balanced reaction changes to oppose a change and reach a new balance

aims to counter the change and restore the previous equilibrium
Le Chatelier-Braun principle
vsLe Chatelier principle
  • Specialized
9.3

A rule saying a balanced system moves to reduce a change and reach a new balance

focuses on restoring balance rather than only moving to a new state
Le Chatelier's law
vsLe Chatelier principle
  • Specialized
8.1

When a balanced chemical system faces a change, it shifts to partly undo the change

describes the general tendency to oppose changes, not only those variables

Surface Forms

Morphology

Le + Chatelier + principle

This is an eponymous scientific name: 'Le Chatelier' is a proper name and provides no semantic clue to the rule's content, while 'principle' only signals that it is a rule. A B1 learner who knows the constituent words would not be able to derive the specific idea about systems shifting to counteract disturbances, so the expression is not compositionally predictable.

Etymology

Le Chatelier principle is often pictured as a balance or seesaw: imagine a system in perfect balance and someone pushes one side. The rest of the system then 'pushes back' to try to 'restore balance', so in chemical reactions a change in temperature, pressure or concentration makes the reaction shift to oppose that change.