Saturday, 11 April 2015

Chemical Balance

chamical balance

The chemical equilibrium is the condition dependent on the temperature in which the concentrations of the chemical species participating in a chemical reaction does not vary in time in total. This occurs when a chemical reaction proceeds with the same speed as the reverse reaction. This means that the rate of consumption of the reactants is equal to that of the formation of the same reagents and this also applies to the products.

Similarly, one can also say that a reaction is at equilibrium when the concentration of products and reactants remains constant, although the reaction is not stopped, in the sense that it continues to take place but not lead to any increase or decrease in concentration of products and reactants, being equal to the values of the two speeds of the reaction, the direct and inverse. As can be guessed from the definition, it is a dynamic equilibrium (non-static).

Strictly speaking, all the chemical reactions should be considered in balance, but, in common practice, those in which the concentrations of the reactants are low (in comparison to the high equilibrium constant) are easily considered non equilibrium (they are known reactions to completion) because the reaction is strongly shifted towards the formation of products.

There are four characteristics common to each equilibrium reaction.

The first, as already said, is the dynamic nature of equilibrium, in which the reaction reaches a situation defined by the equality of the reactions reactant-product and product-reagent.
The second generalization is in the spontaneity of a chemical equilibrium, that is the assertion that a system spontaneously moves towards a state of equilibrium; happen if a disturbance outside the system, when left to itself, would tend to get back into equilibrium (principle of Le Chatelier).

The third is in the statement that a process can be said to be in balance if this is reversible, ie the nature and properties are the same regardless of the direction of approach to equilibrium itself.
The fourth and final generalization consists in the nature of equilibrium thermodynamics, that is, in the vision of the equilibrium state as a condition of more favorable compromise between the natural tendency of the system to reach the minimum energy and the maximum molecular chaos or entropy.