Isibonelo Semibuzo Yengxoxo Nge-Standard Reference Electrode Potential
I-Pendahuluan
I-Electrochemistry iyigatsha le-chemistry elifunda ubudlelwano phakathi kokusabela kwamakhemikhali kanye nezimo zikagesi. Omunye wemibono eyisisekelo ku-electrochemistry yi-electrode potential. I-electrode potential iyisilinganiso sokuthambekela kwe-electrode ekudonseni noma ekukhululeni ama-electron.
Ku-electrochemistry, indinganiso evame ukusetshenziswa yi-standard hydrogen electrode (SHE). I-SHE ichazwa njengenamandla angama-zero volts kuwo wonke amazinga okushisa. Isebenza njengereferensi yendawo yonke yokulinganisa nokuqhathanisa amandla amanye ama-electrode. Lesi sihloko sihlose ukunikeza incazelo eningiliziwe ngezinkinga zezibonelo ezixoxa ngamandla e-standard reference electrode ukuze kuthuthukiswe ukuqonda okujulile.
Amandla e-Electrode kanye ne-SHE
I-SHE isebenza njengendawo yokubhekisela lapho amandla e-electrode ebekwe ngokungahleliwe ku-0 V. Isibalo sokusabela kwe-hydrogen electrode simi kanje:
\[ 2H^+ (aq) + 2e^- \umcibisholo ongakwesokudla H_2 (g) \]
Empeleni, ukulingisa izimo ze-SHE kunzima ukudala futhi kuvame kakhulu ukusebenzisa amanye ama-electrode ajwayelekile okubhekisela njenge-Saturated Calomel Electrode (SCE) noma i-Silver/Silver Chloride (Ag/AgCl).
Imibuzo Nezingxoxo Eziyisibonelo
Umbuzo 1: Ukunquma Amandla E-Electrode Eseli Le-Electrochemical
Umbuzo:
Njengesibonelo senkinga, sicelwa ukuthi sinqume amandla eseli okusabela phakathi kwe-Zn(s) ne-Cu^2+(aq). Kuyaziwa ukuthi amandla e-electrode ajwayelekile e-Zn^2+/Zn angu--0.76 V kanti e-Cu^2+/Cu angu-+0.34 V. Iyini amandla eseli kusetshenziswa i-SHE njengereferensi?
I-Jawaban:
Sidinga ukubala amandla eseli \( E_{cell} \) sisebenzisa amandla e-electrode. Ukusabela okuphelele kuseli yilokhu:
\[ Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s) \]
I-electrode potential ibhalwe kanje:
\[ E_{cell} = E_{cathode} – E_{anode} \]
Lapho i-cathode iyimpendulo yokunciphisa kanti i-anode iyimpendulo ye-oxidation. Ngokusekelwe ku-potential ejwayelekile:
– Amandla ajwayelekile e-Cathode \( E^0_{cathode} \) (Cu^2+/Cu) = +0.34 V
– Amandla ajwayelekile e-anode \( E^0_{anode} \) (Zn^2+/Zn) = -0.76 V
Ukufaka amanani esikhundleni:
\[ E_{sel} = 0.34 \, \umbhalo{V} – (-0.76 \, \umbhalo{V}) \]
\[ E_{sel} = 0.34 \, \umbhalo{V} + 0.76 \, \umbhalo{V} \]
\[ E_{cell} = 1.10 \, \text{V} \]
Ngakho-ke, amandla eseli angu-1.10 V.
Umbuzo 2: Ukusebenzisa i-Nernst Equation Ezimweni Ezingezona Ezijwayelekile
Umbuzo:
Bala amandla eseli (E) ku-298 K ukuze uthole ukusabela kwe-electrochemical phakathi kwe-Zn(s) ne-Cu^2+(aq) uma ukuhlushwa kwama-ion e-Cu^2+ kungu-0.01 M kanti ukuhlushwa kwama-ion e-Zn^2+ kungu-1.00 M.
I-Jawaban:
I-Nernst equation isinikeza indlela yokubala amandla eseli lapho izimo zingekho ezingeni elijwayelekile (ezingekho ezingeni elijwayelekile). I-Nernst equation ithi:
\[ E = E^0 – \frac{RT}{nF} \ln Q \]
Kuphi,
– \( E^0 \) yi-standard cell potential
– \( R \) yi-gas constant (8.314 J/mol·K)
– \( T \) izinga lokushisa ku-Kelvin (298 K)
– \( n \) inani lama-mole ama-electron adluliselwe ku-reaction efanayo (ama-mole ama-2 ama-electron e-Zn/Cu)
– \( F \) kuyinto engaguquki kaFaraday (96485 C/mol)
– \( Q \) yisilinganiso sokusabela:
\[ Q = \frac{[imikhiqizo]}{[ama-reactants]} = \frac{[Zn^{2+}]}{[Cu^{2+}]} \]
Faka amanani ku-equation ye-Nernst:
I-potential ejwayelekile \( E^0 \) evela enkingeni yangaphambilini ingu-1.10 V.
\[ E = 1.10 \, \text{V} – \frac{8.314 \, \text{J/mol·K} \times 298 \, \text{K}}{2 \times 96485 \, \text{C/mol}} \ln \left(\frac{1.00}{0.01}\right) \]
Okokuqala, bala isikhathi sokushisa kanye nesilinganiso sokusabela:
\[ \frac{8.314 \times 298}{2 \times 96485} = \frac{2476.652}{192970} \cishe kube ngu-0.0128 \, \text{V} \]
Ungakhohlwa ukuyiguqula ukuze ifane no-J no-Volts:
\[ \ln (100) = 4.605 \]
Ngakho-ke:
\[ E = 1.10 \, \umbhalo{V} – 0.0128 \izikhathi ezingu-4.605 \]
\[ E = 1.10 \, \umbhalo{V} – 0.0589584 \]
\[ E = 1.041 \, \umbhalo{V} \]
Ngakho-ke, amandla eseli ngaphansi kwezimo ezingezona ezejwayelekile angu-1.041 V.
Isiphetho
I-Electrochemistry iyinsimu ebalulekile enezinhlelo eziningi zokusetshenziswa embonini nasocwaningweni lwesayensi. Ukuqonda imiqondo eyisisekelo njenge-electrode potential kanye nokusetshenziswa kwe-Nernst equation kusenza sikwazi ukubala ama-cell potentials ngaphansi kwezimo ezahlukahlukene. Kulesi sibonelo, sibone indlela yokunquma amandla eseli sisebenzisa i-standard reference electrode nokuthi izici ezifana nokuhlushwa zithinta kanjani amandla eseli.
Le ngxoxo ikhombisa ukubaluleka kokuqonda kahle izimiso ze-electrochemical zezinhlelo zokusebenza ezahlukahlukene, kusukela kuma-biosensor kuya kumabhethri. Iphinde inikeze isisekelo esiqinile kunoma ngubani onentshisekelo ocwaningweni nasekusetshenzisweni kobuchwepheshe be-electrochemical.
