Position du probléme les équilibres chimiques
Question 1 : comment mettre un système chimique hors d’équilibre !?
Question 2: l’évolution d’un système chimique vers un état d’équilibre est-il spontané ou forcé !?
L’équilibre chimique est-il une notion de la thermodynamique ou bien de la cinétique ? Est-il statique ou dynamique ?
Pour connaître plus sur l’équilibre des systèmes chimiques, suivez le lien ci-dessous
Définition les équilibres chimiques
Les équilibres chimiques s’établissent lorsque deux réactions du même système chimique se produisent simultanément dans les mêmes condition , ces équilibres sont dynamiques par opposition aux équilibres physiques qui sont statiques , voir cours sur le lien ci-dessus , comme vous pouvez consulter la leçon sur la page des leçons de physique chimie terminale science du site.
Objectifs : connaître le quotient de la réaction chimique, définir la constante d’équilibre d’un système chimique, connaître que l’équilibre chimique est dynamique, pŕévoir le sens d’évolution d’un système chimique. Définir le taux d’avancement final
Documentation en anglais
Chemical Equilibrium english leson
5.1: Defining EquilibriumA reaction is at equilibrium when the amounts of reactants or products no longer change. Chemical equilibrium is a dynamic process, meaning the rate of formation of products by the forward reaction is equal to the rate at which the products re-form reactants by the reverse reaction.- 5.2: The Equilibrium ConstantThe law of mass action describes a system at equilibrium in terms of the concentrations of the products and the reactants. For a system involving one or more gases, either the molar concentrations of the gases or their partial pressures can be used. The equilibrium constant can be defined in terms of forward and reverse rate constants via the law of mass action.
- 5.3: Heterogeneous EquilibriaAn equilibrated system that contains products and reactants in a single phase is a homogeneous equilibrium; a system whose reactants, products, or both are in more than one phase is a heterogeneous equilibrium.
- 5.4: Predicting Reaction DirectionThe reaction Quotient (\(Q\) or \(Q_p\)) has the same form as the equilibrium constant expression, but it is derived from concentrations obtained at any time. When a reaction system is at equilibrium, \(Q = K\). Graphs derived by plotting a few equilibrium concentrations for a system at a given temperature and pressure can be used to predict the direction in which a reaction will proceed. Points that do not lie on the line or curve are nonequilibrium states.QQ or QpQp) has the same form as the equilibrium constant expression, but it is derived from concentrations obtained at any time. When a reaction system is at equilibrium, Q=KQ=K. Graphs derived by plotting a few equilibrium concentrations for a system at a given temperature and pressure can be used to predict the direction in which a reaction will proceed. Points that do not lie on the line or curve are nonequilibrium states.
- 5.5: Solving Equilibrium ProblemsVarious methods can be used to solve the two fundamental types of equilibrium problems: (1) those in which we calculate the concentrations of reactants and products at equilibrium and (2) those in which we use the equilibrium constant and the initial concentrations of reactants to determine the composition of the equilibrium mixture. When an equilibrium constant is calculated from equilibrium concentrations, concentrations or partial pressures are use into the equilibrium constant expression.
- 5.6: Le Chatelier’s PrincipleSystems at equilibrium can be disturbed by changes to temperature, concentration, and, in some cases, volume and pressure; volume and pressure changes will disturb equilibrium if the number of moles of gas is different on the reactant and product sides of the reaction. The system’s response to these disturbances is described by Le Châtelier’s principle: The system will respond in a way that counteracts the disturbance. Adding a catalyst affects the reaction rates but does not alter equilibrium.
Physique chimie facile 
Alors que tout le monde passe son temps à chercher son équilibre, physique (avoir un corps solide, qui lui permet de garder son équilibre sur le théâtre de la vie) et chimique (avoir un psychique) zen. Il y en a des gens déstabilisé mentalement qui cherchent à faire troubler le monde
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