Mehlala ea Lipotso tse Buisanang ka Tšebeliso ea Lintlha tse ka Khonehang tsa Electrode e Tloaelehileng
Matla a tloaelehileng a electrode (E°) a bapala karolo ea bohlokoa k'hemistri, haholo-holo ho utloisiseng liketso tsa redox le electrochemical. E fana ka mokhoa oa ho bolela esale pele tataiso ea liketso tsa redox le ho bapisa matla a metsoako ea oxidizing le e fokotsang. Sengoloa sena se tla hlahisa mehlala e 'maloa ea ho sebelisa data e tloaelehileng ea matla a electrode ho bontša ts'ebeliso ea eona maemong a sebele.
Selelekela ho Matla a Tloaelehileng a Electrode
Bokgoni ba electrode bo tloaelehileng bo lekanya tšekamelo ea element kapa motsoako ho fumana kapa ho lahleheloa ke lielektrone tlas'a maemo a tloaelehileng (1 M, 1 atm, le 25°C). Bokgoni ba electrode bo tloaelehileng bo hlahisoa ka li-volts (V) 'me hangata bo bapisoa le bokhoni ba electrode ea haedrojene bo tloaelehileng (SHE), bo nkoang e le 0 V.
Mohlala oa Potso ea 1: Ho Fumana Likarabelo tse sa Lebelloang
Potso:
Bala hore na karabelo e latelang e tla etsahala ka tšohanyetso:
\[ \text{Zn}^{2+} + \text{Cu} \rightarrow \text{Zn} + \text{Cu}^{2+} \]
Matla a tloaelehileng a electrode a hlokahalang ke:
– \(\text{Zn}^{2+} + 2e^{-} \rightarrow \text{Zn} \) \( E° = -0.76 \, \text{V} \)
– \(\mongolo{Cu}^{2+} + 2e^{-} \motsu{Cu} \) \( E° = +0.34 \, \mongolo{V} \)
Puisano:
1. Hlalosa Likarabelo tsa Halofo ea Lisele:
Phokotso ea karabelo ea halofo ea sele:
– Karabelo ya halofo ya oxidation: \[\text{Zn}^{2+} + 2e^{-} \rightarrow \text{Zn} \, \text{(Reduction, E° = -0.76 V)} \]
– Phokotso ea karabelo ea halofo: \[\text{Cu}^{2+} + 2e^{-} \rightarrow \text{Cu} \, \text{(Reduction, E° = +0.34 V)} \]
2. Tlhahlobo ea Karabelo:
Fetola karabelo e nang le bokhoni bo tlase e le hore e fetohe oxidation:
– \[\text{Zn} \rightarrow \text{Zn}^{2+} + 2e^{-} \, \text{(Oxidation, E° = +0.76 V)} \]
Likarabelo tse setseng:
– \[\mongolo{Cu}^{2+} + 2e^{-} \motsu \mongolo{Cu} \, \mongolo{(Phokotso, E° = +0.34 V)} \]
3. Bala kakaretso ea E° (Bokhoni ba sele):
– \[ E°_{\text{cell}} = E°_{\text{reduction}} + E°_{\text{oxidation}} = +0.34 \, \text{V} + (+0.76 \, \text{V}) = +1.10 \, \text{V} \]
Kaha bokgoni ba sele (E°_{\text{cell}}) bo botle, karabelo ena e etsahala ka tšohanyetso.
Mohlala oa Potso ea 2: Ho Fumana Bokhoni ba Tekano
Potso:
Bala bokgoni ba sele bakeng sa karabelo e latelang mochesong o tloaelehileng:
\[ \text{Fe}^{2+} + \text{Ag} \rightarrow \text{Fe} + \text{Ag}^{+} \]
Bokhoni bo tloaelehileng ba elektrode:
– \(\text{Fe}^{2+} + 2e^{-} \rightarrow \text{Fe} \) \( E° = -0.44 \, \text{V} \)
– \(\text{Ag}^{+} + e^{-} \rightarrow \text{Ag} \) \( E° = +0.80 \, \text{V} \)
Puisano:
1. Hlalosa Likarabelo tsa Halofo ea Lisele:
Phokotso ea karabelo ea halofo ea sele:
– \[\text{Fe}^{2+} + 2e^{-} \rightarrow \text{Fe} \, \text{(Reduction, E° = -0.44 V)} \]
– \[\text{Ag}^{+} + e^{-} \rightarrow \text{Ag} \, \text{(Reduction, E° = +0.80 V)} \]
2. Hlalosa Likarabelo tse Halofo:
Khutlisa karabelo e nang le boleng bo bobe bo bonyenyane (bo botle haholoanyane):
– \[\text{Fe} \rightarrow \text{Fe}^{2+} + 2e^{-} \, \text{(Oxidation, E° = +0.44 V)} \]
Likarabelo tse setseng:
– \[\text{Ag}^{+} + e^{-} \rightarrow \text{Ag} \, \text{(Reduction, E° = +0.80 V)} \]
3. Bala kakaretso ea E° (Bokhoni ba sele):
– \[ E°_{\text{cell}} = E°_{\text{reduction}} + E°_{\text{oxidation}} = +0.80 \, \text{V} + (+0.44 \, \text{V}) = +1.24 \, \text{V} \]
Bokgoni bo botle ba sele bo bontsha hore karabelo ena e etsahala ka boithatelo tlasa maemo a tloaelehileng.
Mohlala oa 3: Palo ea Matla a Mahala a Gibbs
Potso:
Fumana phetoho ea matla a mahala a Gibbs (ΔG) bakeng sa karabelo e latelang:
\[ \text{Al} + \text{Cu}^{2+} \rightarrow \text{Al}^{3+} + \text{Cu} \]
Ho latela bokgoni bo tloaelehileng ba electrode:
– \(\text{Al}^{3+} + 3e^{-} \rightarrow \text{Al} \) \( E° = -1.66 \, \text{V} \)
– \(\mongolo{Cu}^{2+} + 2e^{-} \motsu{Cu} \) \( E° = +0.34 \, \mongolo{V} \)
Puisano:
1. Hlalosa Likarabelo tsa Halofo ea Lisele:
Phokotso ea karabelo ea halofo ea sele:
– \[\text{Al}^{3+} + 3e^{-} \rightarrow \text{Al} \, \text{(Reduction, E° = -1.66 V)} \]
– \[\mongolo{Cu}^{2+} + 2e^{-} \motsu \mongolo{Cu} \, \mongolo{(Phokotso, E° = +0.34 V)} \]
2. Tlhahlobo ea Karabelo:
Fetola karabelo e nang le bokhoni bo tlase e le hore e fetohe oxidation:
– \[\text{Al} \rightarrow \text{Al}^{3+} + 3e^{-} \, \text{(Oxidation, E° = +1.66 V)} \]
Likarabelo tse setseng:
– \[\mongolo{Cu}^{2+} + 2e^{-} \motsu \mongolo{Cu} \, \mongolo{(Phokotso, E° = +0.34 V)} \]
3. Tekanyo ea elektrone:
Lekanya palo ea lielektrone bakeng sa karabelo:
– 2 \(\text{Al} \rightarrow 2\text{Al}^{3+} + 6e^{-} \) \[\text{(Oxidation, E° = +1.66 V)} \]
– 3 \(\ mongolo{Cu}^{2+} + 6e^{-} \ motsu 3\mongolo{Cu} \) \[\ mongolo{(Phokotso, E° = +0.34 V)} \]
4. Bala kakaretso ea E° (Bokhoni ba sele):
– \[ E°_{\text{cell}} = (+0.34 \, \text{V} \times 3) + (+1.66 \, \text{V} \times 2) \]
Phoso mona: Karolelano:
– \[ E°_{\text{cell}} = +0.34 \, \text{V} + +1.66 \, \text{V} = +2.00 \, \text{V}\]
5. Bala ΔG:
Foromo: \(\Delta G = -nFE_{\text{cell}}\)
– \[n = 6 \, \mongolo{li-electrone} \]
– \[F = 96485 \, \mongolo{C/mol} \]
– \[ \Delta G = -6 \times 96485 \, \text{C/mol} \times +2.00 \, \text{V}\]
- \[ = -1157820 \, \ mongolo{J/mol} \]
– \[ = -1157.82 \, \ mongolo{kJ/mol}\]
Kahoo, ΔG e mpe e bontša hore karabelo ena e etsahala ka tšohanyetso.
Qetello
Lintlha tse tloaelehileng tsa bokhoni ba electrode li fana ka mokhoa o sebetsang oa ho bolela esale pele hore na karabelo ea redox e tla tsoela pele ka lehlakoreng lefe, hore na ho ka etsahala hore e tsoele pele hakae, le kamano ea eona le phetoho ea matla a mahala a Gibbs. Bothata ba mohlala bo kaholimo bo bontša kamoo lintlha tsena li ka sebelisoang ho fumana ho iketsahalla ha karabelo ea redox le lipalo tsa matla tse amanang le tsona. Bakeng sa baithuti kapa mang kapa mang ea ithutang k'hemistri, ho utloisisa lintlha tse tloaelehileng tsa bokhoni ba electrode le lits'ebetso tsa eona ke motheo oa bohlokoa oa ho utloisisa likarabelo tse rarahaneng tsa electrochemical.
