Applications of Le-Chatelier’s Principle
Some of the applications of Le-Chatelier’s principle are listed below: 1. In the Study of Physical Equilibrium (A) Effect of temperature on solubility: Some solids absorb heat while some evolve heat on dissolution. Hence according to this principle solubility of the former class of solids increases with rise of temperature. For example: (i) (ii) With rise of temperature solubility of increases while that of decreases. (B) Effect of pressure on solubility: Since on dissolution of gas volume decreases, hence on increasing...
read moreLaw of Mass Action and Heterogeneous System
Law of Mass Action and Heterogeneous System: (i) Dissociation of calcium carbonate : If is heated in a closed vessel, a portion of it usually decomposes forming CaO (solid) and (gas) and ultimately an equilibrium is set up according to the equation; The active mass of a solid is constant at a definite temperature and independent of the amount of solid present. We may, therefore, regard it as a homogeneous equilibrium in the gas phase, in which solids are present with a constant partial pressure or active mass. convention (at all...
read moreLaw of Mass Action and Homogeneous System
Law of Mass Action and Homogeneous System: (i) Dissociation of HI: Let ‘a’ mole of gaseous ‘HI’ be heated and let ‘x’ mole each of be formed at the equilibrium. For the reaction, If ‘V’ be the volume of the system, then the molar concentrations at equilibrium are: Applying the law of mass action to the system, we have Or, This equilibrium constant, ‘K’ can also be written as and in this type of reaction because the total number of moles remain unchanged. I. e., ...
read moreTypes of Equilibrium
There are two kinds of chemical equilibrium such as homogeneous equilibrium in which all the reactants and products are in the same phase and heterogeneous equilibrium in which reactants and products are in different phases. To illustrate the concentration of the reactants and products at equilibrium two examples are given below: (i) Synthesis of nitric oxide: The synthesis of NO from may be given as: Where ‘a’ and ‘b’ are the number of moles/litre of the reactants initially respectively. Let x be the degree of dissociation...
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Guldberg and Waage (1884) put forward the law of mass action. It states that, “At constant temperature, the rate of a chemical reaction is directly proportional to the active mass of the reactant present at that time. If more than one reactant takes part in the reaction then the rate of the reaction is proportional to the product of the active masses of the reactants.” Active mass means the concentration of the substance expressed in mole per litre or the pressure of a reacting gas in atmosphere. It is usually denoted oy putting the symbol...
read moreLe Chatelier’s principle
In order to study the effect of change in temperature, pressure or concentration on the state of equilibrium Le Chatelier and Braunna (1884) enunciated a general principle which is known as Le Chate1ier’s principle. According to this principle, “if a system in equilibrium is subjected to a change in concentration, temperature or pressure, then the equilibrium automatically shifts in such a way that the effect of the changed condition is nullified”. According to this principle we may conclude that: (i) The increase of...
read moreCharacterstics and Factors Influencing Equilibrium constant
Characteristics of Equilibrium Constant 1. It has a definite value for every chemical reaction at a given temperature. 2. It is independent of concentrations of the reactants and products. 3. It is not effected by the presence of catalyst. 4. It is a convenient measure of the extent to which the reaction proceeds in a particular direction at a given temperature. Factors Influencing Equilibrium Constant 1. Stoichiometic representation of reaction: Consider the following reactions: 2. The mode of representing the change:...
read moreChemical Equilibrium
Equilibrium exhibits the state of a process at which the measurable properties of the system do not show any change with time. The term chemical equilibrium is used for the chemical reaction when the concentration of the reactants and the products does not change with time. We consider the following reactions: (i) ii) (iii) (Closed vessel) (iv) (Haber’s process) Since the reactions (i) and (ii) proceed in one direction and the reaction is completed with time hence these are known as irreversible reactions....
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