Mohlala oa Lipotso tsa Puisano mabapi le Bokhoni ba Electrode ea Referense e Tloaelehileng
Pendahuluan
Electrochemistry ke lekala la k'hemistri le ithutang kamano pakeng tsa dikarabelo tsa dikhemikhale le diketsahalo tsa motlakase. E 'ngoe ea likhopolo tsa motheo ho electrochemistry ke electrode potential. Electrode potential ke tekanyo ea tšekamelo ea electrode ho hohela kapa ho lokolla dielektrone.
Ho electrochemistry, tekanyetso e sebelisoang haholo ke electrode e tloaelehileng ea haedrojene (SHE). SHE e hlalosoa e le e nang le bokhoni ba li-volt tsa zero mochesong oohle. E sebetsa e le referense ea bokahohle bakeng sa ho lekanya le ho bapisa bokhoni ba li-electrode tse ling. Sehlooho sena se ikemiselitse ho fana ka tlhaloso e qaqileng ka mathata a mehlala a buang ka bokhoni ba electrode e tloaelehileng ea referense ho holisa kutloisiso e tebileng.
Bokgoni ba Electrode le SHE
SHE e sebetsa e le ntlha ea litšupiso moo bokhoni ba electrode bo behiloeng ka mokhoa o sa reroang ho 0 V. Tekanyo ea karabelo ea electrode ea haeterojene ke e latelang:
\[ 2H^+ (aq) + 2e^- \ motsu H_2 (g) \]
Ha e le hantle, ho etsisa maemo a SHE ho thata ho a etsa mme ho tlwaelehile haholo ho sebedisa di-electrode tse ding tse tloaelehileng tsa referense tse kang Saturated Calomel Electrode (SCE) kapa Silver/Silver Chloride (Ag/AgCl).
Lipotso le Lipuisano tsa Mehlala
Potso ea 1: Ho Fumana Bokhoni ba Electrode ba Sele ea Electrochemical
Potso:
Mohlala oa bothata, re kopuoa ho fumana bokhoni ba sele ba karabelo lipakeng tsa Zn(s) le Cu^2+(aq). Hoa tsebahala hore bokhoni bo tloaelehileng ba electrode bakeng sa Zn^2+/Zn ke -0.76 V mme bakeng sa Cu^2+/Cu ke +0.34 V. Bokhoni ba sele ke bofe ho sebelisoa SHE e le referense?
Karabo:
Re hloka ho bala bokgoni ba sele \( E_{cell} \) re sebedisa bokgoni ba electrode. Karabelo yohle ka hara sele ke:
\[ Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s) \]
Bokgoni ba electrode bo ngotswe tjena:
\[ E_{sele} = E_{cathode} – E_{anode} \]
Moo cathode e leng karabelo ea phokotso 'me anode e le karabelo ea oxidation. Ho ipapisitsoe le bokhoni bo tloaelehileng:
– Cathode bokgoni ba maemo \( E^0_{cathode} \) (Cu^2+/Cu) = +0.34 V
– Bokgoni bo tloaelehileng ba anode \( E^0_{anode} \) (Zn^2+/Zn) = -0.76 V
Ho nkela boleng sebaka:
\[ E_{sel} = 0.34 \, \text{V} – (-0.76 \, \text{V}) \]
\[ E_{sel} = 0.34 \, \mongolo{V} + 0.76 \, \mongolo{V} \]
\[ E_{sele} = 1.10 \, \mongolo{V} \]
Kahoo, bokgoni ba sele ke 1.10 V.
Potso ea 2: Ho Sebelisa Nernst Equation Maemong a sa Tloaelehang
Potso:
Bala bokgoni ba sele (E) ho 298 K bakeng sa karabelo ya electrochemical pakeng tsa Zn(s) le Cu^2+(aq) haeba mahloriso a di-ion tsa Cu^2+ e le 0.01 M mme mahloriso a di-ion tsa Zn^2+ e le 1.00 M.
Karabo:
Tekanyo ea Nernst e re fa mokhoa oa ho bala bokhoni ba sele ha maemo a sa tloaeleha (a sa tloaelehang). Tekanyo ea Nernst ke:
\[ E = E^0 – \frac{RT}{nF} \ln Q \]
Di mana,
– \( E^0 \) ke bokgoni bo tloaelehileng ba sele
– \( R \) ke khase e sa fetoheng (8.314 J/mol·K)
– \( T \) ke mocheso ho Kelvin (298 K)
– \( n \) ke palo ea li-mole tsa lielektrone tse fetisetsoang karabelong e lekanang (li-mole tse 2 tsa lielektrone bakeng sa Zn/Cu)
– \( F \) ke kamehla ea Faraday (96485 C/mol)
– \( Q \) ke quotient ea karabelo:
\[ Q = \frac{[lihlahisoa]}{[li-reactant]} = \frac{[Zn^{2+}]}{[Cu^{2+}]} \]
Kenya boleng sebakeng sa equation ea Nernst:
Bokgoni bo tloaelehileng \( E^0 \) ho tsoa bothateng bo fetileng ke 1.10 V.
\[ E = 1.10 \, \text{V} – \frac{8.314 \, \text{J/mol·K} \times 298 \, \text{K}}{2 \times 96485 \, \text{C/mol}} \ln \left(\frac{1.00}{0.01}\right) \]
Taba ea pele, bala nako ea mocheso le quotient ea karabelo:
\[ \frac{8.314 \times 298}{2 \times 96485} = \frac{2476.652}{192970} \hoo e ka bang 0.0128 \, \text{V} \]
Se lebale ho e fetolela ho bapisa J le Volts:
\[ \ln (100) = 4.605 \]
Kahoo:
\[ E = 1.10 \, \mongolo{V} – 0.0128 \makgetlo a 4.605 \]
\[ E = 1.10 \, \ mongolo{V} – 0.0589584 \]
\[ E = 1.041 \, \mongolo{V} \]
Kahoo, bokgoni ba sele tlasa maemo a sa tlwaelehang ke 1.041 V.
Qetello
Electrochemistry ke tšimo ea bohlokoa e nang le lits'ebetso tse ngata lipatlisisong tsa indasteri le tsa mahlale. Ho utloisisa likhopolo tsa motheo tse kang bokhoni ba electrode le ts'ebeliso ea equation ea Nernst ho re lumella ho bala bokhoni ba sele tlas'a maemo a fapaneng. Mohlaleng ona, re bone mokhoa oa ho fumana bokhoni ba sele re sebelisa electrode e tloaelehileng ea referense le kamoo lintlha tse kang mahloriso li amang bokhoni ba sele.
Puisano ena e bonts'a bohlokoa ba kutloisiso e batsi ea melao-motheo ea lik'hemik'hale tsa motlakase bakeng sa mefuta e mengata ea lits'ebetso, ho tloha ho li-biosensor ho isa ho libeteri. E boetse e fana ka motheo o tiileng bakeng sa mang kapa mang ea nang le thahasello lipatlisisong le lits'ebetsong tsa theknoloji ea lik'hemik'hale tsa motlakase.
