Ngā Tauira Pātai e Matapaki ana i te Whakataurite i ngā Pūtau Pūngao me ngā Pūtau Hikohiko
He kaupapa nui te whakatairite i waenga i ngā pūtau hiko me ngā pūtau hikohiko i roto i te matū, inā koa i roto i te ako i te hikohiko. He taputapu e rua e whakamahia ana hei whakaputa hiko mai i ngā tauhohenga matū, hei whakahaere rānei i ngā tauhohenga matū mā te whakamahi i te pūngao hiko. Ka whakamāramahia e tēnei tuhinga ngā rerekētanga matua i waenga i ngā pūtau hikohiko me ngā pūtau hikohiko mā roto i ngā tauira rapanga me ngā kōrero. Ko te whāinga he whakarato i tētahi māramatanga hōhonu me te hohonu mō ngā momo pūtau e rua.
Pūtau Pūngao
Ko te pūtau hiko, e mōhiotia ana ko te pūtau karawaka, he momo pūtau hikohiko e whakaputa ana i te iahiko hiko mai i tētahi tauhohenga matū ohorere. I roto i te pūtau hikohiko, ka puta he tauhohenga redox, ka puta te whakaiti me te waikura i ngā irahiko rerekē. Hei mārama ake i tēnei, me titiro tātou ki tētahi tauira o te pūtau hikohiko.
Tauira Pātai 1:
He mea hanga te anode o te pūtau hikohiko ki te konutea (Zn) me te cathode ki te parahi (Cu). Mēnā ka tirohia he ripanga o ngā pūmanawa whakaiti paerewa, e whakaatu ana ko te pūmanawa whakaiti paerewa (E°) o Cu²⁺/Cu he +0,34 V, ā, ko te pūmanawa whakaiti paerewa o Zn²⁺/Zn he -0,76 V. Tātaihia te pūmanawa pūtau paerewa (E°) o tēnei pūtau hikohiko.
Kōrero:
Tuatahi, tuhia ngā tauhohenga haurua-pūtau mō te waikura me te whakaiti.
– Anode (Waikura): Zn(s) → Zn²⁺(aq) + 2e⁻
– Cathode (Whakaiti): Cu²⁺(aq) + 2e⁻ → Cu(s)
Ka tatauhia te pūmanawa pūtau paerewa (pūtau E°) mai i te rerekētanga o te pūmanawa whakaiti o te katote me te anote.
– E° pūtau = E° cathode – E° anode
– E° katote = +0,34 V
– E° te āwhata = -0,76 V
Nō reira, ko te pūmanawa pūtau paerewa ko:
\[ E°_{sel} = 0.34V – (-0.76V) \]
\[ E°_{pūtau} = 0.34V + 0.76V \]
\[ E°_{sel} = 1.10V \]
Nō reira, ko te pūmanawa paerewa o te pūtau mō tēnei pūtau hiko he 1,10 V.
Pūtau Hikohiko
Ko ngā pūtau hikohiko ia, ka whakamahi i te pūngao hiko hei akiaki i ngā tauhohenga matū kore-ā-pūmanawa kia puta. I roto i te pūtau hikohiko, ka whakamahia he iahiko hiko mai i tētahi pūtake o waho hei akiaki i tētahi tauhohenga redox e kore e puta ko ia anake. Me titiro tātou ki tētahi tauira o te pūtau hikohiko kia mārama ai ki ōna āhuatanga me ngā mātāpono mahi.
Tauira Pātai 2:
I roto i te tukanga hikohiko, ka puta te konumohe mai i te waikura konumohe rewa (Al₂O₃). Tātaihia te nui o te hiko e hiahiatia ana hei whakaputa i te 1 mole o te konumohe (Al). Me kī kotahi mole o te Al e toru ngā mole o ngā irahiko e hiahiatia ana.
Kōrero:
E ai ki te whārite hikohiko mō te electrolysis:
\[ Al^{3+}(aq) + 3e⁻ → Al(s) \]
E mōhiotia ana mō ia irahiko o te konumohe, e 3 irahiko o ngā irahiko e hiahiatia ana. E ai ki te ture a Faraday, ka taea te tatau i te nui o te hiko (Q) e hiahiatia ana mā te whakamahi i te tātai:
\[ Q = n \cdot F \]
kāore i te mana:
– ko n te maha o ngā mole o ngā irahiko
– Ko F te pūmau o Faraday (96500 C/mol ngā irahiko)
Hei whakaputa i te 1 mole o te Al:
\[ n = 3 \text{ ngā mole o ngā irahiko} \]
Nō reira, ko te nui o te hiko (Q):
\[ Q = 3 \cdot 96500 \]
\[ Q = 289500 \kuputuhi{ C} \]
Nō reira, hei whakaputa i te 1 mole o te konumohe, e 289500 coulombs o te hiko e hiahiatia ana.
Te Whakataurite i ngā Pūtau Pūngao me ngā Pūtau Hikohiko
Kei te ripanga e whai ake nei ngā rerekētanga matua i waenga i ngā pūtau hiko me ngā pūtau hikohiko:
| Ngā Āhuatanga | Pūtau Pūngaohiko | Pūtau Hikohiko |
|—————————–|————————————|——————————–|
| Ngā Pūtake Pūngao | Ngā Tauhohenga Matū | Pūngao Hiko |
| Momo Tauhohenga | Ātaahua | Kore-ātaahua |
| Ānōta (-)/Kātōta (+) | Ānōta (-), Kātōta (+) | Ānōta (+), Kātōta (-) |
| Kaupapa | Whakaputa hiko | Whakaoho i ngā tauhohenga matū |
| Ngā Whakamahinga | Ngā Pūhiko, ngā pūtau wahie | Te whakakikorua, te whakarewa whakarewa, te whakamahine |
Ngā Pūtake Pūngao:
Ka whakaputahia e ngā pūtau pūngao hiko te pūngao hiko mai i ngā tauhohenga matū tūpono, ko ngā pūtau hiko ia ka whakamahi i te pūngao hiko mai i tētahi pūtake o waho hei akiaki i ngā tauhohenga kore-tūpono kia puta.
Momo Tauhohenga:
I roto i te pūtau hiko, ka rere ngā irahiko mai i te anode ki te cathode mā te ara iahiko o waho i te tauhohenga ohorere. I roto i te pūtau hikohiko, ka whakamahia he iahiko o waho hei akiaki i tētahi tauhohenga kāore e puta ko ia anake.
Te Anode me te Cathode:
I roto i te pūtau hikohiko, ko te anode te irahiko kino, ā, ko te cathode te irahiko pai. I roto i te pūtau hikohiko, ko te anode te irahiko pai, ā, ko te cathode te irahiko kino. Koinei tētahi o ngā rerekētanga matua e whakapoauau ana i ngā ākonga.
Kaupapa:
Ko te kaupapa matua o te pūtau hiko he whakaputa hiko, ko te pūtau hikohiko ia e whakamahia ana hei whakaoho i ngā tauhohenga matū, pērā i te whakamahine whakarewa, te hikohiko wai rānei.
Taupānga:
He mea noa te whakamahi i ngā pūtau hiko i roto i ngā pākahiko me ngā pūtau wahie, e whakaputa ana i te hiko mō ngā momo mahi. E whakamahia ana ngā pūtau hikohiko i roto i ngā tukanga ahumahi pēnei i te whakarewa whakarewa, te whakakikorua hiko, me te whakamahine whakarewa.
Whakamutunga
He mea nui te mahi a ngā pūtau hikohiko me ngā pūtau hiko-whakawhiti i roto i ngā hangarau o ēnei rā. Ko te mārama ki te mahi a ia momo pūtau me te tatau i ngā tawhā rerekē mā roto i ngā tauira rapanga he mea nui ki te mōhio ki ngā ariā hiko-whakawhiti. I roto i te kōrero i runga ake nei, kua whakamāramahia e mātou ngā rerekētanga matua i waenga i ngā pūtau hiko-whakawhiti me ngā pūtau hiko-whakawhiti, tae atu ki ō rātou pūtake pūngao, ngā momo tauhohenga, me ngā tauira o ā rātou whakamahinga i roto i te oranga o ia rā.
Mā te mārama pai ki ēnei momo pūtau e rua, ka pai ake tō rite ki te whakaoti rapanga e pā ana ki ngā whakamātautau matū, me te whakamahi i aua rapanga ki ngā taputapu me ngā hangarau hou.
