1. Department of Bioorganic and Biological Chemistry. Bioinorganic chemistry. I COURSE LECTURER: Professor A.D.DZHURAEV LECTURE 6. THE BASE OF ELECTROCHEMISTRY

2. THE LECTURE PURPOSE: Study of the phenomena occurring in biological systems, in the flow of electric current through them is of great importance for medicine. Different diagnostic and therapeutic techniques of electrophysiology and physiotherapy based on the properties of the fluids and tissues of the body - to conduct electric current, electrodiagnosis is used in a number of diseases of the nervous and muscular system in order to determine the change in muscle responses to stimulation of the motor nerves of electric shock. Electroexitability change as the motor nerve and muscle supplied by them, there is in some diseases of the neuromuscular system, and due to this it is possible to determine the region and degree of the neuromuscular system. Have an understanding of electrotherapy treatments - electrical stimulation, galvanization, electrophoresis, diathermy induktometrii, frequency therapy and other human body fluids-blood, plasma, serum, saliva, etc., to some extent conduct electricity and can be considered as electrolytes.

3. THE LECTURE PURPOSE: Acquaint the students with conduction of electrolyte solutions as the study of the phenomena, appearing in biological systems at running through them electric current have great importance for medicine. Different diagnostic and therapeutic methods electrophysiology and physical therapy founded on property c of the liquids and tissue of organism to conduct the electric current. Electro diagnostics is used at row of the diseases nervous and muscular system for the reason determinations of the change reaction of muscles and motor nerve on irritation their by electric current. A change of electro exciting both motor nerve, and supplied by him muscles, occurs at some disease nervously-muscular device, and due to this manages to install the area and degree of the breach nervously-muscular device. Are they broadly used in medical practices the electric current and electromagnetic fields. So, electro therapeutics methods of the treatment are electro stimulation, galvanization, electrophoresis, diathermy, inductometry, ultrahigh-frequency therapy and others In this connection to future physician necessary to know the electric characteristics an organs and liquids of the organism at different disease. The methods of the determination of conduction are broadly used in medicine as exists the certain relationship between different pathological changes in organism of the person and conduction of blood, urines, gastric juice and others biological liquids.

4. D EALT of questions Basics of Electrochemistry, the theoretical framework that is the ability of substances to conduct electricity Factors determining the electrical conductivity of the electrolyte Methods for determining the degree and the dissociation constant of electrolyte solutions by using the values ​​ of electrical conductivity Conductometric titration

5. Basics of Electrochemistry Any body conducting the electrical current is called a conductor. In conductors 1st kind electric current arises only because of the motion of electrons, metals, metal alloys, carbon, graphite, and others. In conductors 2nd kind or they are called electrolytes passage of electric current soprovozhaetsya chemical changes: salt solutions, acids, bases, melts soluble metal oxides.

6. Conductivity of electrolyte solutions Ability of electrolyte solutions conduct electric current is called conductivity. conductivity 1 L = ------ ом -1 R resistance: L R =  ------- ; S

7. Conductivity of electrolytic solutions 1 S L = ------  -----, ohm (1/  ) = æ  l S L = æ ------ ohm -1 l specific conductivity (æ) 1 L æ = ------  -----, ohm -1 sm -1 R S

8. Conductivity of electrolytic solutions The molar conductivity = æ  1000 or = æ  1000  v æ  1000 = ------------ ohm 1  sm 2  mole -1 C

9. Kohlrausch law Equivalent electrical conductivity equal to the amount of cations and anions λ ∞ = λ c + λ а, where λ к and λ а - mobility of cations and anions. λ к = F*U K and λ а, = F * U a where U c и U a - the absolute speed of the cations and anions, λ ∞ = F*U C + F * U a = F (U c + U a ). λ = К * а.

10. Determination  electrolytes by conductometry = К   ; Ом -1  см 2 моль -1 If  = 1, то = К and reaches a value , i.e. = . because and  и К equal, that К can be replaced by , as a result : =    ohm -1  cm 2  mol - -1. hence :  - the degree of dissociation  = ------ ; - molar conductivity   - conductivity at infinite dilution

11. Determination K diss. electrolytes by conductometry C   2 C  2 K= ------- or K = ---------------- 1-   ( -  )

12. Conductometric titration Titration of a strong acid with a strong base æ HCl +NaOH equivalence point. V NaOH,мл

13. Conductometric titration Titration of a weak acid with a strong base æ CH 3 COOH + NaOH equivalence point V NaOH,мл

14. Conductometric titration Titration of a mixture of strong and weak acid with a strong base æ HCl + CH 3 COOH + NaOH equivalence point.1 equivalence point 2 V NaOH,мл