Le Chatelier's principle Henry Louis Le Châtelier

le chatelier s principle states system acts oppose changes in chemical equilibrium; restore equilibrium, system favor chemical pathway reduce or eliminate disturbance restabilize @ thermodynamic equilibrium. put way,

if chemical system @ equilibrium experiences change in concentration, temperature or total pressure, equilibrium shift in order minimize change.

this qualitative law enables 1 envision displacement of equilibrium of chemical reaction.

for example: change in concentration of reaction in equilibrium following equation:

n2(g) + 3h2(g) ⇌ 2nh3(g)

if 1 increases pressure of reactants, reaction tend move towards products decrease pressure of reaction.

however consider example: in contact process production of sulfuric acid, second stage reversible reaction:

2so2(g) + o2(g) ⇌ 2so3(g)

the forward reaction exothermic , reverse reaction endothermic. viewed le chatelier s principle larger amount of thermal energy in system favor endothermic reverse reaction, absorb increased energy; in other words equilibrium shift reactants in order remove stress of added heat. similar reasons, lower temperatures favor exothermic forward reaction, , produce more products. works in case, since due loss of entropy reaction becomes less exothermic temperature increases; reactions become more exothermic temperature increases seem violate principle.