15. Describe spectrochemical series of ligands. The concept of crystal field stabilization energy (cfse) and stability of the complexes

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16. Factors affecting the chemical equilibrium constant and do not affect it (give examples), its significance in practice. Relationship with the magnitude of the Free Energy.

characteristic chemical equilibrium is a quantity that called the chemical equilibrium constant.

When an external impact to the system is a shift of chemical equilibrium, in other words change the equilibrium concentrations of the starting materials and reaction products. If as a result of external influences increase the equilibrium concentration of the reaction products, then talk about shifting the equilibrium to the right. If as a result of external influences increase the equilibrium concentration of the starting materials, in other word a shift of the equilibrium to the left. Character displacement under the influence of external effects can be described by the principle of Le Chatelier: If the system is in equilibrium have an impact from the outside, then amplified the processes in the system, which reduces an impact. Consider the effect of changing some settings on the shift of equilibrium: 1) a change in the concentration of substances. Increasing the concentration of the reactants shifts the equilibrium toward their expenditure. 2) the influence of the total pressure in the system. Increasing the pressure equilibrium of the system shifts the equilibrium toward the formation of smaller volumes. 3) the effect of temperature. With increasing temperature, the equilibrium shifts toward the endothermic reactions t.e.reaktsy, which provides a flow temperature absorption. The equilibrium constant of the reaction is related to the standard Gibbs energy change equation: ΔG0 = - RTlnKp. This equation makes it possible, knowing ΔG0, calculate the equilibrium constant and, conversely, the experimentally found value of the equilibrium constant of the reaction to determine ΔG0.

17. Nature of chemical bonding in metals. Electronic band structure.

18. Describe influence of temperature on rate of chemical reaction. Give determination of Vant-Hoff’s law and write the Arhenius’s equation.

With increasing temperature, the chemical reaction rate increases. According to the rule of van't Hoff: the temperature is raised for every 100 reaction rate increases by 2-4 times. A number indicating how many times the increase of the reaction rate when the temperature rises to 100, called the temperature coefficient and is denoted by γ. Let the reaction rate at t₁ through v_t1, and when t₂ through v_t2, then:

 v_t2 = v_t1 * γ ^ ((t2-t1) / 10). Arrhenius equation establishes a relationship constant chemical reaction rate K of the temperature T. According to a simple model of the collision a chemical reaction between the two starting materials can only occur as a result of the collision molecule substances. But not every collision leads to a chemical reaction. It is necessary to overcome a certain energy barrier to molecules began to react with each other. That is, molecules must have a certain minimum energy to overcome this barrier. Boltzmann distribution for the kinetic energy of the molecules is known that the number of molecules with energy E> EA, proportionally. As a result of the chemical reaction rate it is represented by an equation which has been obtained by the Swedish chemist Svante Arrhenius from thermodynamic considerations: K = Ae ^ (- Ea / RT). Here, A characterizes the frequency of collisions of the reacting molecules, R - universal gas constant.

  In the framework of the theory of the activated complex derived from the other depending on the temperature of A, but in all cases, weaker than the exhibitor. Arrhenius equation has become one of the basic equations of chemical kinetics and activation energy - an important quantitative characteristic reactivity of substances.