spontaneously flow processes in systems of open and closed types described by specific criteria, known as Gibbs energy.It is the function of the state.DUGibbs, working with thermodynamic systems, managed to bring it through the entropy and enthalpy.Gibbs energy, in particular, makes it possible to predict the direction of the flow of spontaneous biological processes and evaluate them theoretically achievable efficiency.
If you apply the findings of Gibbs to the second thermodynamic law, the wording is as follows: at constant (const) pressure and temperature without forcing the system can support a spontaneous occurrence but such processes, which result in a decrease in the level of the Gibbs energy to a value that occurs when theit established a minimum.The balance of any thermodynamic system is the immutability of this energy (at least).Therefore, the Gibbs energy is a potential (free enthalpy) in the isobaric-isothermal systems.Explain why it was not at least.The fact that this is one of the important principles in equilibrium thermodynamics: this state at constant temperature and pressure means that the next change in the energy level should be increased, and this is possible only by changing any external factors.
code letters - G. numerically equal to the difference between the known value of the enthalpy and entropy in the temperature of the product.That is the Gibbs energy can be expressed through the following formula:
G = H - (S * t),
where S - the entropy of the system;t - temperature thermodynamic;H - enthalpy.The entropy of the system included in this formula to take into account the fact that high temperature reduces the ordered state of the system (disorder), and the lowest - on the contrary.
Since both the Gibbs energy, enthalpy, and - one of the functions of the system in thermodynamics, that by changing the G or H can be described occurring chemical transformations.If given reaction equation and Gibbs energy change, then it belongs to the class of thermochemical.
regard to this energy can be formulated Rule Hess: if the pressure and temperature constant, the creation of new substances from the initial (basic reagents) leads to the fact that the energy of the system changes, with the kind of place reactions, and their number is the result notinfluence.
Since energy is referred to in the article is a variable quantity, to perform calculations introduced the concept of "standard Gibbs energy."This value is present in any chemical catalog, numerically equal to 298 kJ / mol (note that the dimension is the same as for any other molar energy).This value allows you to calculate the change in virtually any chemical process.
If during the course of a chemical reaction in the system is an external action (work done), then the value of the Gibbs energy increases.Such reactions are referred to endergonic.Accordingly, if the system itself does work, spending power, we are talking about ekzergonicheskih manifestations.
Gibbs energy concept has found wide application in modern chemistry.For example, the synthesis of polymers based on the addition reaction.If they hold several particles are combined into one, and the entropy decreases.Based on the formula of Gibbs, it could be argued that the external effects (eg, high temperature) may draw a similar exothermic addition reaction, which is confirmed in practice.
