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№1 слайд![Electrochemistry](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img0.jpg)
Содержание слайда: Electrochemistry
Oxidation-reduction equilibrium in water solutions.
№2 слайд![oxidation reductant oxidant](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img1.jpg)
Содержание слайда: oxidation
reductant oxidant + ne
reduction
ΔGo = - 2,3·RT·lgK – chemical work
ΔGo = - nF؏o - electrical work
؏= E2 – E1
E – red-ox potential
№3 слайд![](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img2.jpg)
№4 слайд![Criteria for spontaneous](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img3.jpg)
Содержание слайда: Criteria for spontaneous
red-ox reactions
Mn+7 + 5Fe+2 Mn+2 + 5Fe+3
EoMn+7/Mn+2 = 1,51 В; EoFe+3/Fe+2 = 0,77 В
EoMn+7/Mn+2 > EoFe+3/Fe+2
Mn+7 + 5ē → Mn+2
oxidant
Fe+2 - ē → Fe+3
reductant
ΔGo = -nF؏o
ΔGo < 0 for spontaneous reaction
؏o = 1,51 – 0,77 = 0,74 V
ΔGo = -5·96500·0,74 = -357050 J = -357,050 kJ.
№5 слайд![Red-ox potentials of](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img4.jpg)
Содержание слайда: Red-ox potentials
of biological systems
reductant oxidant + 2e + 2 H+
ΔGo = -2F؏o
Oxidant - acceptor of electrons and protons
№6 слайд![Electrodes](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img5.jpg)
Содержание слайда: Electrodes
№7 слайд![type-electrodes Me Me n metal](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img6.jpg)
Содержание слайда: 1 type-electrodes
Me Me+n – metal electrode
Me Me+n + ne
Pt(H2) H+ - hydrogen electrode
H2 2H+ + 2e
№8 слайд![Hydrogen electrode](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img7.jpg)
Содержание слайда: Hydrogen electrode
№9 слайд![type-electrodes Hg Hg Cl ,](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img8.jpg)
Содержание слайда: 2 type-electrodes
Hg Hg2Cl2, KCl – calomel electrode
Ag AgCl, KCl – silver chloride electrode
Ag Ag+ + Cl-
In saturated KCl solutions
ESC = const.=0.202V
Ecal. = const. = 0.244V
№10 слайд![Silver chloride and calomel](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img9.jpg)
Содержание слайда: Silver chloride and calomel electrodes
№11 слайд![Redox electrodes Pt ox, red](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img10.jpg)
Содержание слайда: Redox electrodes
Pt | ox, red
№12 слайд![Quinhydrone electrode Pt QH H](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img11.jpg)
Содержание слайда: Quinhydrone electrode
Pt (QH) H+
№13 слайд![Nernst equation for electrode](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img12.jpg)
Содержание слайда: Nernst equation
for electrode potential
ΔGo = - 2,3·RT·lgK – chemical work
ΔGo = - nF (E0 – E) - electrical work
Eox/red = E0ox/red + (2,3RT/nF) lgK
2,3RT/F = 0.059 at T = 2890K, F= 96500, R=8.31
Eox/red = E0ox/red + (0.059/n) lg[ox]/[red]
E0ox/red – standard potential
№14 слайд![Hydrogen electrode Pt H H Н Н](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img13.jpg)
Содержание слайда: Hydrogen electrode
Pt (H2) | H+
½ Н2 Н+ + ē
Eox/red = E0ox/red + (0.059/n) lgK
EН2 = E0Н2 + (0.059/1) lg[H+]
E0Н2 = 0
Standard potential of hydrogen electrode
EН2 = - 0.059 pH
№15 слайд![Nernst equation for](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img14.jpg)
Содержание слайда: Nernst equation
for biological redox system
reductant oxidant + 2e + 2 H+
Eox/red =E0ox/red + (0.059/2) lg[ox][H+]2/[red]
Eox/red = E0ox/red – 0.059pH + 0.03 lg[ox]/[red]
№16 слайд![Nernst equation for](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img15.jpg)
Содержание слайда: Nernst equation for biological redox system
at pH = 7
Eox/red = E0ox/red – 0.059pH + 0.03 lg[ox]/[red]
E0ox/red – 0.059pH = E0ox/red – 0.059 . 7
E0’ox/red = E0ox/red – 0.41
Standard potential of biological system at pH = 7
Eox/red = E0’ox/red + 0.03 lg[ox]/[red]
№17 слайд![Quinhydrone electrode Pt QH H](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img16.jpg)
Содержание слайда: Quinhydrone electrode
Pt (QH) H+
Eox/red = E0ox/red – 0.059pH + 0.03 lg[ox]/[red]
EQH = E0QH – 0.059pH + 0.03lg[quinone]/[hydroquinone]
Quinhydrone = 1M quinone + 1Mhydroquinone
EQH = E0QH – 0.059pH
№18 слайд![Galvanic electrochemical cell](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img17.jpg)
Содержание слайда: Galvanic (electrochemical) cell
Zn | ZnSO4(р- р) || CuSO4(р- р) | Cu
№19 слайд![electromotive force EMF](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img18.jpg)
Содержание слайда: electromotive force (EMF)
electromotive force (EMF)
؏= E2 – E1
؏о = ЕoCu – ЕoZn = 0,34 – ( - 0,76) = 1,1B
CuSO4 + Zn → ZnSO4 + Cu
reductant Zno - 2ē → Zn2+ oxidation
oxidant Cu2+ + 2ē → Cuo reduction
№20 слайд![Potentiometry](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img19.jpg)
Содержание слайда: Potentiometry
№21 слайд![Potentiometry](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img20.jpg)
Содержание слайда: Potentiometry
№22 слайд![. Calculate the potential of](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img21.jpg)
Содержание слайда: 1. Calculate the potential of quinhydronе electrode in the 0.01M solution of HF. pKHF= 4, E0QH= 0.699V
1. Calculate the potential of quinhydronе electrode in the 0.01M solution of HF. pKHF= 4, E0QH= 0.699V
2. What is the degree of dissociation of a weak acid, if the equilibrium potential of hydrogen electrode immersed into the 0.2M solution of this acid is equal to - 0.18V?
3. Estimate the value of ΔG0’ and determine the direction of spontaneous reaction:
NADH + H+ + ethanal NAD+ + ethanol
E0’NAD+/NADH= - 0.32V, E0’ethanal/ethanol= - 0.20V.
№23 слайд![. Estimate the value of the](/documents_6/f6810eb4f5ef9f8ae385765137f19fa7/img22.jpg)
Содержание слайда: 4. Estimate the value of the equilibrium potential of platinum electrode in the solution of two salts: FeCl2 (0.25M) and FeCl3 (0.25M), E0Fe3+/Fe2+= 0.77V, t= 250C.
4. Estimate the value of the equilibrium potential of platinum electrode in the solution of two salts: FeCl2 (0.25M) and FeCl3 (0.25M), E0Fe3+/Fe2+= 0.77V, t= 250C.
5. Determine the ratio of concentrations [fumarate]/[succinate] if the potential of platinum electrode in this solution is equal to 0.04V, t= 250C, E0’fum/suc= - 0.031V, pH = 7.
6. Diagram the cell consisting of the silver chloride electrode in saturated KCl solution and hydrogen electrode in the 0.01M solution of acetic acid . What is the electromotive force (EMF) of this cell? pKCH COOH = 4.75, ESC=0.202V