CHAPTER(1) – Chemical Equilibrium

Concept of free energy

Free energy is a thermodynamic function like enthalpy and entropy. It is also known as free enthalpy. Free energy is used to determine the changes made by a system and how much work it produced. It is expressed in two forms i.e. (1) Helmholtz free energy                                                              (2) Gibb’s free energy Gibbs free energy: It …

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Le-Chatelier’s principle

Le-Chatelier’s principle: This is based on the fundamental of a stable equilibrium. It states,when a system at equilibrium is subjected to a change in temperature,pressure or concentration of a reacting species,the system react in a way that partially offset the change while reaching a new state of equilibrium. Effect of concentration: If the concentration of …

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Important relationship involving equilibrium constant

1. If we reverse an equation  KP or  KC  is reversed.            If              A + B ⇔ C + D         KC = 10             then for    C + D ⇔ A + B          KC = 10-1 2. If we multiply each of the coefficient in a balanced equation by a factor n,then equilibrium constant is raised to the same factor. ½ N2 + …

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Relationship between Kp ,Kc, Kx and Kn

Kp=Equilibrium constant in terms of partial pressure. Kc=Equilibrium constant in terms of concentration. Kx=Equilibrium constant in terms of  mole fraction. Kn=Equilibrium constant in terms of  number of moles.  Kp and Kc are related as  KP = KC (RT)∆n ………………………(eq 1)         Relationship between KP and Kn             ………………………(eq 2)     …

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Equilibrium constant in terms of partial pressure.

 Both KP and Kc  are equilibrium constants,but  Kc  is defined by molar concentration    but  KP is defined by partial pressure. Derivation of KP : Consider the following reversible reaction                  aA(g) + bB(g) ⇔ cC(g) + dD(g)  If equilibrium constant for the reaction  is expressed in terms of the molar concentration ,             If the equilibrium involves gaseous species, then concentration may be expressed in terms …

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Law of mass action/Law of chemical equilibrium

Principle of Chemical equilibrium: This theory was proposed by Goldberg and Waage in 1884. According to this law ,rate of reaction at a given temperature is directly proportional to the product of active masses of the reactants, raised to the power equal to stoichiometric co- efficient of the balanced chemical equation at a particular instant of reaction. …

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