Lipotso tsa Mehlala Puisano ea Lisele tsa Electrochemical: Ho Utloisisa Metheo ea Electrochemistry ka Lipotso tsa Mehlala
Electrochemistry ke lekala la k'hemistri le ithutang kamano pakeng tsa dikarabelo tsa dikhemikhale le motlakase. Ho electrochemistry, hangata re buisana ka mefuta e 'meli e meholo ea lisele: lisele tsa galvanic (kapa voltaic) le lisele tsa electrolytic. Mefuta ka bobeli ea lisele e sebelisa dikarabelo tsa redox ho hlahisa kapa ho sebelisa motlakase.
Sehloohong sena, re tla tšohla mehlala e meng ea lisele tsa electrochemical tse tla re thusa ho tebisa kutloisiso ea rona ea mohopolo ona.
1. Potso: Sele ea Galvanic
Mohlala, ha re nke sele ea galvanic e nang le electrode ea zinki (Zn) e qoelitsoeng ka har'a tharollo ea ZnSO₄ le electrode ea koporo (Cu) e qoelitsoeng ka har'a tharollo ea CuSO₄. Ngola likarabelo tse hlahang ho electrode ka 'ngoe, hammoho le karabelo e akaretsang sele ena ea galvanic.
Puisano:
1. Karabelo ho electrode ea zinki (anode, oxidation):
Karabelo: \( Zn(s) \rightarrow Zn^{2+}(aq) + 2e^- \)
Mona, zinki e oxidized ho ba ioni ea zinki (Zn²⁺) 'me e ntša lielektrone tse peli.
2. Karabelo ho electrode ea koporo (cathode, phokotso):
Karabelo: \( Cu^{2+}(aq) + 2e^- \li-Cu(s) \)
Mona, li-ion tsa koporo (Cu²⁺) li amohela lielektrone tse peli 'me li fokotsoa ho ba koporo e tiileng (Cu).
3. Karabelo e akaretsang ka seleng ea galvanic:
Kopanya likarabo tsena tse peli tsa halofo ho fumana karabelo ka kakaretso:
\( Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s) \)
Ka kakaretso, ho ka fihlellwa qeto ea hore liseleng tsa galvanic, ho iketsahalla ha liketso tsa redox ho sebelisoa ho hlahisa motlakase.
2. Potso: Bokgoni ba Sele
Ha ho nahanoa ka bokgoni bo tloaelehileng ba phokotso bakeng sa Zn²⁺/Zn = -0,76 V le Cu²⁺/Cu = +0,34 V. Bala bokgoni ba sele ba sele ya galvanic bo buisantsweng pejana.
Puisano:
Bokgoni ba sele (E°_cell) bo ka balwa ho sebediswa equation:
\[
E°_{sele} = E°_{cathode} – E°_{anode}
\]
Moo:
– Cathode ke electrode moo phokotso e etsahalang (Cu²⁺/Cu ka E° = +0.34 V)
– Anode ke electrode moo ho etsahalang oxidation (Zn²⁺/Zn ka E° = -0.76 V)
\[
E°_{sel} = 0.34\, V – (-0.76\, V) = 0.34\, V + 0.76\, V = 1.10\, V
\]
Ka hona, bokgoni ba sele ba sele ya galvanic ke 1,10 V.
3. Potso: Sele ea Electrolytic
Seleng ea electrolytic, tharollo ea sodium chloride (NaCl) e lokisoa ka hare ho sele ea electrolytic e nang le li-electrode tse sa sebetseng. Ngola likarabelo tse hlahang ho electrode ka 'ngoe.
Puisano:
Seleng ea electrolytic, motlakase o sebelisoa ho khanna karabelo e sa reroang. Seleng ea electrolytic e nang le tharollo ea NaCl, re na le:
1. Karabelo ho cathode (phokotso):
\[
2H_2O(l) + 2e^- \ motsu o ka ho le letona H_2(g) + 2OH^-(aq)
\]
Litharollong tse ngata tsa NaCl tse hlapolotsoeng, metsi a tla fokotseha pele ho sodium hobane bokhoni ba phokotso ea metsi bo molemo haholo (-0.83 V) ho feta sodium (-2.71 V).
2. Karabelo ho anode (oxidation):
\[
2Cl^-(aq) \ motsu o nepahetseng Cl_2(g) + 2e^-
\]
Ho anode, li-ion tsa chloride li fetoloa khase ea chlorine.
3. Karabelo ka kakaretso:
Kopanya dikarabelo ho cathode le anode bakeng sa karabelo e akaretsang:
\[
2H_2O(l) + 2Cl^-(aq) \ motsu o ka ho le letona H_2(g) + Cl_2(g) + 2OH^-(aq)
\]
Ka electrolysis ena ea metsi a letsoai, khase ea haedrojene le khase ea chlorine li hlahisoa hammoho le tharollo ea motheo (NaOH) ka lebaka la tšebelisano ea li-ion tse ka har'a tharollo.
4. Potso: Melao ea Faraday ea Electrolysis
Ke digrama tse kae tsa koporo tse tswang tharollong ya CuSO₄ haeba matsatsi a 2 a faraday a motlakase a feta ka hara tharollo?
Puisano:
Molao oa Faraday o bolela hore bongata ba ntho e beiloeng holim'a electrode nakong ea electrolysis bo lekana le bongata ba motlakase o fetang ho eona. Boima ba ntho (m) bo ka baloa ho sebelisoa equation:
\[
m = \frac{M \cdot Q}{n \cdot F}
\]
Moo:
– \(m\) ke boima ba ntho e kentsweng
– \(M\) ke boima ba molar ba ntho (bakeng sa Cu, M = 63.5 g/mol)
– \(Q\) ke tjhelete ya tjhaja ya motlakase (ka di-coulombs, e balwang e le \(Q = n \cdot F\), moo n e leng palo ya matsatsi a faraday)
– \(n\) ke palo ea li-mole tsa lielektrone tse amehang karabelong (bakeng sa Cu²⁺/Cu, n = 2)
– \(F\) ke kamehla ea Faraday (96500 C/mol)
Ka motlakase oa 2 faraday:
\[
m = \frac{63.5\, g/mol \cdot 2 \cdot 96500\, C}{2 \cdot 96500\, C/mol}
\]
Nolofatsa equation:
\[
m = 63.5\, g
\]
Sephetho e bile hore digrama tse 63.5 tsa koporo di ile tsa kenngwa ka electrolysis ena.
Qetello
Ho utloisisa lisele tsa electrochemical ho hloka tsebo ea likarabelo tsa redox, lipalo tsa bokhoni ba sele, le stoichiometry ea electrochemical. Ho utloisisa mathata a mohlala a kang a kaholimo ho thusa ho hlakisa likhopolo tsa motheo le ts'ebeliso ea tsona mefuteng e fapaneng ea lisele tsa electrochemical. Qetellong, tsoela pele ho ikoetlisa ka mathata a fapaneng ho tebisa kutloisiso ena, haholo-holo bakeng sa lits'ebetso tsa khopolo-taba le tse sebetsang mafapheng a fapaneng a saense le indasteri.
