Muenzaniso weMibvunzo yeKukurukurirana yeElectrochemistry
Electrochemistry ibazi rekemesitiri rinoongorora hukama huripo pakati pemakemikoro nekuchinja kwesimba remagetsi. Mu electrochemistry, kune pfungwa huru mbiri: oxidation (kuburitswa kwemaerekitironi) uye kuderedza (kuwedzera kwemaerekitironi). Maitiro aya anogona kuonekwa mumhando mbiri dzemasero emagetsi: masero evoltaic (masero egalvanic) uye masero eelectrolytic. Pazasi pane mimwe mienzaniso yematambudziko netsananguro dzawo kuti zvikubatsire kunzwisisa electrochemistry.
Muenzaniso Mubvunzo 1: Sero reVoltaic
Mubvunzo:
Kana wapiwa sero revoltaic rine maelectrode e zinc (Zn) ne copper (Cu) akabatana kuburikidza ne salt bridge. Zn inonyikwa mu 1 M ZnSO4 solution uye Cu inonyikwa mu 1 M CuSO4 solution. Nyora pasi reactions dzinoitika pa electrode yega yega uye verenga potential difference (EMF) ye voltaic cell. Standard electrode potential data:
\[ E^o_{\text{Zn}^{2+}/\text{Zn}} = -0.76 \, \text{V} \]
\[ E^o_{\chinyorwa{Cu}^{2+}/\chinyorwa{Cu}} = +0.34 \, \zvinyorwa{V} \]
Kukurukurirana:
Danho rekutanga nderekuona kuti chii chinonzi redox reaction chinoitika. Musero revoltaic, chiitiko chinonzi spontaneous redox reaction chinoitika apo
– Zinc (Zn) inooxidation:
\[ \text{Zn (s)} \rightarrow \text{Zn}^{2+} (aq) + 2e^- \]
– Mhangura (Cu) inoderedzwa:
\[ \chinyorwa{Cu}^{2+} (aq) + 2e^- \museve wekurudyi \zvinyorwa{Cu (s)} \]
Mhinduro yakazara ye redox mu voltaic cell ndeiyi:
\[ \text{Zn (s)} + \text{Cu}^{2+} (aq) \rightarrow \text{Zn}^{2+} (aq) + \text{Cu (s)} \]
Tevere, tichaverenga musiyano wesimba remaseru:
\[ E_{\text{cell}} = E^o_{\text{cathode}} – E^o_{\text{anode}} \]
Dimana:
– Cathode ndiyo electrode apo kuderedzwa (Cu) kunoitika.
– Anode ndiyo electrode apo oxidation (Zn) inoitika.
Kuti,
\[ E_{\text{sel}} = 0.34 \, \text{V} – (-0.76 \, \text{V}) \]
\[ E_{\text{sel}} = 0.34 \, \text{V} + 0.76 \, \text{V} = 1.10 \, \text{V} \]
Mhedziso:
– Maitiro anoitika pa anode (Zn):
\[ \text{Zn (s)} \rightarrow \text{Zn}^{2+} (aq) + 2e^- \]
– Maitiro anoitika pa cathode (Cu):
\[ \chinyorwa{Cu}^{2+} (aq) + 2e^- \museve wekurudyi \zvinyorwa{Cu (s)} \]
– Musiyano wesimba remasero (EMF): 1.10 V
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Muenzaniso Mubvunzo 2: Sero reElectrolytic
Mubvunzo:
Mukushandiswa kwemagetsi eNaCl solution, taura maitiro anoitika pa cathode ne anode kana electrode isina simba, yakaita seplatinum (Pt), ikashandiswa. Verenga huwandu hwese hunodiwa kuti uwane 1 gram yeCl2. (Ar Cl = 35.5)
Kukurukurirana:
Danho rekutanga nderekunyora pasi maitiro anoitika pa electrode yega yega muNaCl salt solution.
– Pa cathode (kuderedza):
Mukuita uku, H+ ions kubva mumvura dzichaderedzwa:
\[ 2H_2O(l) + 2e^- \museve wekurudyi H_2(g) + 2OH^-(aq) \]
– Pa anode (oxidation):
Iyo Cl-ion ichapiswa kuti ive Cl2 gasi:
\[ 2Cl^-(aq) \museve wekurudyi Cl_2(g) + 2e^- \]
Mhinduro Yose:
Saka mhinduro yese inoitika mu electrolysis yeNaCl solution ndeiyi:
\[ 2NaCl(aq) + 2H_2O(l) \museve wekurudyi 2NaOH(aq) + H_2(g) + Cl_2(g) \]
Kuti tiverenge mutengo unodiwa kuti tigadzire 1 gramu yeCl2, tinofanira kuona huwandu hwemamoles eCl2:
\[ \text{Mass yeCl}_2 = 1 \text{gram} \]
\[ \text{Ar Cl}_2 = 2 \times 35.5 = 71 \text{ gram/mol} \]
\[ \text{Nhamba yemamoles eCl}_2 = \frac{1}{71} \text{ mol} \]
Zvichibva pa reaction equation pa anode, 1 mol yeCl2 inogadzirwa kubva ku2 mol yemaerekitironi:
\[ 2Cl^- \museve wekurudyi Cl_2 + 2e^- \]
Nemamwe mashoko, mole imwe yeCl2 inoda mamore maviri emaerekitironi.
Huwandu hwemamorekuru emaerekitironi:
\[ \text{Nhamba yemamore emaerekitironi} = 2 \times \frac{1}{71} = \frac{2}{71} \text{ mol} \]
Mari inodiwa inogona kuverengerwa uchishandisa Faraday value (F = 96485 C/mol e^-):
\[ Q = n \nguva F \]
\[ Q = \left(\frac{2}{71} \text{ mol}\right) \times 96485 \text{ C/mol} \]
\[ Q = 2718 \chinyorwa{ C} \]
Mhedziso:
- Mhinduro pa cathode:
\[ 2H_2O(l) + 2e^- \museve wekurudyi H_2(g) + 2OH^-(aq) \]
- Mhinduro pa anode:
\[ 2Cl^-(aq) \museve wekurudyi Cl_2(g) + 2e^- \]
– Mari yose inodiwa kuti pagadzirwe 1 gram yeCl2 i2718 C.
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Muenzaniso 3: Nernst Relationship uye Non-Standard Conditions
Mubvunzo:
Verenga kugona kwesero revoltaic rakagadzirwa kubva kumaelectrode eAg/Ag+ ane silver ion concentration ye0.1 M uye Zn/Zn2+ electrodes ane concentration ye0.01 M. Iyo standard electrode potential ndeiyi:
\[ E^o_{\text{Ag}^{+}/\text{Ag}} = +0.80 \, \text{V} \]
\[ E^o_{\text{Zn}^{2+}/\text{Zn}} = -0.76 \, \text{V} \]
Kukurukurirana:
Danho rekutanga nderekunyora pasi maitiro anoitika:
– Kuokisijeni pa anode (Zn):
\[ \text{Zn (s)} \rightarrow \text{Zn}^{2+} (aq) + 2e^- \]
- Kuderedza pa cathode (Ag):
\[ \text{Ag}^{+} (aq) + e^- \rightarrow \text{Ag (s)} \]
Kupindura kwese:
\[ \text{Zn (s)} + 2\text{Ag}^{+} (aq) \rightarrow \text{Zn}^{2+} (aq) + 2\text{Ag (s)} \]
Zvichibva paNernst equation:
\[ E_{\text{Cell}} = E^o_{\text{Cell}} – \left( \frac{0.0592}{n} \right) \log \left( \frac{[\text{product}]}{[\text{reactant}]} \right) \]
Dimana:
\[ n = 2 \]
Kutanga, verenga E^o_{\text{Sel}}:
\[ E^o_{\text{Sel}} = E^o_{\text{Ag}^{+}/\text{Ag}} – E^o_{\text{Zn}^{2+}/\text{Zn}} \]
\[ E^o_{\text{Sel}} = 0.80 \, \text{V} – (-0.76 \, \text{V}) \]
\[ E^o_{\text{Cell}} = 1.56 \, \text{V} \]
Zvadaro, verenga kugona kwemasero chaiwo pahuwandu hwakapihwa:
\[ E_{\text{Sel}} = 1.56 \, \text{V} – \left( \frac{0.0592}{2} \right) \log \left( \frac{[\text{Zn}^{2+}]}{[\text{Ag}^{+}]^2} \right) \]
\[ E_{\text{Sel}} = 1.56 \, \text{V} – \left( \frac{0.0592}{2} \right) \log \left( \frac{0.01}{(0.1)^2} \right) \]
\[ E_{\text{Cell}} = 1.56 \, \text{V} – 0.0296 \log \left( \frac{0.01}{0.01} \right) \]
\[ E_{\text{Cell}} = 1.56 \, \text{V} \]
Mhedziso:
- Maitiro anoitika pa anode ne cathode anoramba akafanana
- Simba remasero rine huwandu hwakatarwa i1.56 V
Chinyorwa chino chinoratidza maitiro ekugadzirisa matambudziko akasiyana-siyana mu electrochemistry, kusanganisira matambudziko ane chekuita ne voltaic cells, electrolytic cells, uye kuverenga uchishandisa Nernst Equation. Kunzwisisa zvakakwana misimboti iri shure kwe redox reactions uye kugona kushandisa electrochemical data zvakakosha kuti ubudirire mukugadzirisa matambudziko aya.
