Imibuzo yemizekelo exoxa ngee-Voltaic Cells
I-Pendahuluan
Iseli ye-voltaic, ekwaziwa ngokuba yi-galvanic cell, sisixhobo esiguqula amandla eekhemikhali abe ngamandla ombane ngokusebenzisa i-redox (i-oxidation-reduction). Iseli ye-voltaic inee-electrodes ezimbini, ezenziwe ngeentsimbi ezahlukeneyo, ezifakwe kwi-electrolyte kwaye ziqhagamshelwe yibhulorho yetyuwa. Kweli nqaku, siza kuxoxa ngemizekelo eliqela enxulumene neeseli ze-voltaic ukuze siqonde ngakumbi imigaqo yazo yokusebenza kunye nendlela yokubala amandla eseli.
Ingcamango Esisiseko yeeSeli zeVoltaic
Ngaphambi kokuba uqhubekele kwiingxaki zemizekelo, kubalulekile ukuqonda iingcamango ezisisiseko kunye nezinto ezenza iseli yeVoltaic:
1. I-Anode kunye neCathode: Kwiseli yeVoltaic, i-anode yi-electrode apho kwenzeka khona i-oxidation, kwaye i-cathode yi-electrode apho kwenzeka khona ukuncipha. I-anode ine-negative charge, ngelixa i-cathode ine-positive charge.
2. Indlela ye-Electron: Ii-electron zihamba ukusuka kwi-anode ukuya kwi-cathode ngesekethe yangaphandle, zivelisa umsinga wombane.
3. I-Cell Potential (E°cell): I-Cell potential ngumahluko onokubakho phakathi kwee-electrodes ezimbini. I-Standard cell potential (E°cell) ingabalwa kusetyenziswa le fomyula:
\[
E°cell = E°cathode – E°anode
\]
apho \(E°cathode\) kunye \(E°anode\) zizinto ezisemgangathweni zokunciphisa amandla e-cathode kunye ne-anode.
4. Ibhuloho yeTyuwa: Le bhuloho ilinganisa iindleko ze-ion kuzo zombini izisombululo ze-electrolyte ngokuvumela ukuhamba kwee-ion.
Imibuzo yeSampuli kunye neNgxoxo
Ukuze sicacise ezi ngcamango, makhe sixoxe ngemizekelo yeengxaki.
Umzekelo Umbuzo 1
Umbuzo:
Bala amandla eseli aqhelekileyo eseli yeVolta equlathe ii-electrode ze-Zn | Zn²⁺ (aq) kunye nee-electrode ze-Cu | Cu²⁺ (aq). Kuyaziwa ukuba amandla okunciphisa aqhelekileyo \(E°\) kwi-Zn²⁺ | Zn yi--0.76 V kunye ne-\(E°\) kwi-Cu²⁺ | I-Cu yi-+0.34 V.
Ingxoxo:
Inyathelo lokuqala kukufumanisa ukuba yeyiphi i-anode kunye ne-cathode.
I-Zn inamandla okunciphisa angaphantsi (-0.76 V) kune-Cu (+0.34 V), ngoko ke i-Zn iya kusebenza njenge-anode (indawo yokuxovula) kunye ne-Cu njenge-cathode (indawo yokunciphisa).
Okulandelayo, sisebenzisa le fomyula:
\[
E°cell = E°cathode – E°anode
\]
Faka amaxabiso aziwayo endaweni yawo:
\[
Iseli ye-E = 0.34 V – (-0.76 V)
\]
\[
Iseli ye-E = 0.34 V + 0.76 V
\]
\[
Iseli ye-E = 1.10 V
\]
Ngoko ke, amandla eseli aqhelekileyo yi-1.10 V.
Umzekelo Umbuzo 2
Umbuzo:
Iseli yeVoltaic yenziwe ngee-electrodes zeFe | Fe²⁺ kunye nee-electrodes zeAg | Ag⁺. Amandla okunciphisa aqhelekileyo eFe²⁺ | Fe yi -0.44 V kwaye kwiAg⁺ | Ag yi +0.80 V. Bala amandla okusebenzisa iiseli aqhelekileyo kwaye ubhale impendulo yeseli.
Ingxoxo:
Njengangaphambili, kufuneka simisele i-anode kunye ne-cathode. Ekubeni amandla okunciphisa i-Fe²⁺/Fe engaphantsi kune-Ag⁺/Ag, i-Fe iya kusebenza njenge-anode kwaye i-Ag ibe yi-cathode.
Sebenzisa le fomyula:
\[
E°cell = E°cathode – E°anode
\]
\[
Iseli ye-E = 0.80 V – (-0.44 V)
\]
\[
Iseli ye-E = 0.80 V + 0.44 V
\]
\[
Iseli ye-E = 1.24 V
\]
Amandla eseli aqhelekileyo yi-1.24 V.
Kwimpendulo iyonke yeseli, sidibanisa i-oxidation kunye ne-reduction reactions:
– Impendulo kwi-anode: \( \text{Fe} \rightarrow \text{Fe}^{2+} + 2\text{e}^- \)
– Impendulo kwi-cathode: \( \text{Ag}^+ + \text{e}^- \rightarrow \text{Ag} \)
Ukulinganisela inani lee-electron kuzo zombini iimpendulo:
\[
\text{Fe} \rightarrow \text{Fe}^{2+} + 2\text{e}^-
\]
\[
2\text{Ag}^+ + 2\text{e}^- \rightarrow 2\text{Ag}
\]
Impendulo iyonke yeseli:
\[
\text{Fe} + 2\text{Ag}^+ \rightarrow \text{Fe}^{2+} + 2\text{Ag}
\]
Umzekelo Umbuzo 3
Umbuzo:
Bala amandla eseli kwi-25°C kwiseli yeVoltaic equlathe ii-electrode ze-Al | Al³⁺ kunye nee-electrode ze-Ni | Ni²⁺, ukuba uxinzelelo lwe-Al³⁺ yi-0.001 M kwaye uxinzelelo lwe-Ni²⁺ yi-1 M. Kuyaziwa ukuba \(E°\) kwi-Al³⁺ | Al yi--1.66 V kunye \(E°\) kwi-Ni²⁺ | Ni yi--0.23 V.
Ingxoxo:
Okokuqala, misela i-anode kunye ne-cathode:
– Amandla okunciphisa i-Al³⁺/Al angaphezulu kwe-negative (-1.66 V) kune-Ni²⁺/Ni (-0.23 V), ngoko ke i-Al yi-anode kwaye i-Ni yi-cathode.
I-standard cell potential ibalwa ngolu hlobo:
\[
E°cell = E°cathode – E°anode
\]
\[
Iseli ye-E = -0.23 V – (-1.66 V)
\]
\[
Iseli ye-E = -0.23 V + 1.66 V
\]
\[
Iseli ye-E = 1.43 V
\]
Okulandelayo, sisebenzisa iNernst Equation ukubala amandla eseli phantsi kweemeko ezingezizo ezisemgangathweni:
\[
E_{cell} = E°cell – \left( \frac{RT}{nF} \right) \ln Q
\]
Apho \( Q = \frac{[\text{Al}³⁺]}{[\text{Ni}²⁺]} \), u-R yi-gas constant (8.314 J/mol·K), u-T yi-temperature eKelvin (298 K kwi-25°C), u-F yi-Faraday constant (96485 C/mol), kwaye u-n linani lee-electron (6 yee-reactions ezibandakanya u-Al³⁺ kunye no-Ni²⁺).
Faka amaxabiso aziwayo kwi-equation:
\[
Q = \frac{0.001}{1} = 0.001
\]
\[
E_{cell} = 1.43 V – \left( \frac{8.314 \times 298}{6 \times 96485} \right) \ln 0.001
\]
\[
I-E_{cell} = 1.43 V – \left( \frac{2477.172}{578910} \right) \ln 0.001
\]
\[
I-E_{cell} = 1.43 V – (0.00428) \ln 0.001
\]
\[
\ln 0.001 = -6.907
\]
\[
I-E_{cell} = 1.43 V – (0.00428 \amaxesha -6.907)
\]
\[
I-E_{cell} = 1.43 V + 0.0295
\]
\[
I-E_{iseli} = 1.4595 V
\]
Ngoko ke, amandla eseli kule meko amalunga ne-1.46 V.
Ukuqukumbela
Iseli ye-voltaic yingcamango esisiseko kwi-electrochemistry eguqula amandla eekhemikhali abe ngamandla ombane. Eli nqaku lizise iziseko zethiyori yeseli ye-Voltaic kwaye linike imizekelo yokunceda ukucacisa inkqubo yokubala amandla eseli. Ngolu lwazi, abafundi baya kuba nokuqonda okungcono ngeeseli ze-Voltaic kunye nokusetyenziswa kwazo kwiimeko ezahlukeneyo.
