Ngā Tukanga Waikura me te Whakaiti i roto i te Matū Hiko
Ko te matū hikohiko he peka o te matū e ako ana i te whanaungatanga i waenga i ngā tauhohenga matū me te hiko. I roto i te matū hikohiko, ko te ariā tino taketake e puta tonu ana ko ngā tauhohenga waikura me te whakaiti (redox). Mā roto i ngā tauhohenga waikura, ka taea e ngā irahiko te neke mai i tētahi matū ki tētahi atu. Ko tēnei whakawhiti irahiko he "piriti" i waenga i ngā huringa matū me te pūngao hiko, ahakoa i roto i ngā pākahiko, i ngā kaiwhakaemi, i ngā pūtau wahie, i ngā tukanga ahumahi rānei pērā i te whakakikorua hiko me te whakamahine konganuku. Mā te mārama ki te mahi a te waikura me te whakaiti ka āwhina i a tātou ki te mārama he aha te pākahiko ka taea te whakaputa i te iahiko hiko, me pēhea rānei te tukanga o te electrolysis e taea ai te huri i tētahi matū hei ōna huānga.
Te Mārama ki te Waikura me te Whakaiti
Ki te kī māmā noa, ko te waikura te tukanga tuku i ngā irahiko, ko te whakaiti ia ko te tukanga whiwhi irahiko. I roto i te tauhohenga redox, ka puta tahi te waikura me te whakaiti nā te mea me whakaae ngā irahiko e tukuna ana e tētahi matū ki tētahi atu matū.
Haunga te whakamāramatanga e ahu mai ana i ngā irahiko, tera atu anō ētahi huarahi hei mōhio ki te waikura me te whakaiti:
1. I runga i te tau waikura (tau ox):
– Te waikura: ka piki te tau waikura o tētahi huānga.
– Whakaitinga: ka heke te tau waikura o tētahi huānga.
2. I runga i te hāora me te hauwai (te whakamāramatanga tawhito):
– Te waikura: te tāpiritanga o te hāora, te whakaititanga rānei o te hauwai.
– Te whakaiti: te tango i te hāora, te tāpiri rānei i te hauwai.
Heoi, i roto i te matū hiko, ko te whakamāramatanga tino whaihua ko te whakamāramatanga e hangai ana ki te irahiko: ka ngaro ngā irahiko i te waikura, ka whiwhi ngā irahiko i te whakaiti.
Tauhohenga-haurua i roto i te Redox
I roto i te matū hiko, ka wehea ngā tauhohenga redox kia rua ngā tauhohenga-haurua:
– Tauhohenga waikura (anodic): ka ngaro ngā irahiko i tētahi matū
Ngā tauira noa:
\[
\kāhua{Zn} \rightarrow \kāhua{Zn}^{2+} + 2e^-
\]
– Tauhohenga whakaiti (katotika): ka whiwhi te matū i ngā irahiko
Ngā tauira noa:
\[
\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}
\]
Mā te wehewehe i te tauhohenga ki ngā tauhohenga-haurua, ka taea e tātou te aru mārama ake i te rere o ngā irahiko, me te whakangāwari ake hoki i te taurite o ngā tauhohenga redox, inā koa i raro i ngā āhuatanga waikawa, taketake rānei.
Ngā Pūtau Hikohiko: Te Wāhi e Tūtaki ai ngā Tauhohenga me te Hiko
He pūnaha te pūtau hikohiko e whakamahi ana i ngā tauhohenga redox hei whakaputa, hei whakamahi rānei i te pūngao hiko. E rua ngā momo matua:
1. Ngā pūtau hiko/pūtau hiko (ka whakaputa hiko aunoa)
Tauira: ngā pākahiko me ngā pūtau Daniell.
2. Ngā pūtau hikohiko (e whakamahi ana i te hiko hei akiaki i ngā tauhohenga kore-ā-pūmanawa)
Tauira: te whakapūkara wai, te whakakikorua whakarewa (whakapūkara hiko).
Kei roto i ēnei pūtau e rua he anode me he cathode, engari he mea nui kia maumahara: ko te anode tonu te wāhi o te waikura, ko te cathode ia te wāhi o te whakaiti. Ko te mea anake e rerekē ana ko te tohu o te utu hiko, i runga i te momo pūtau.
Te Waikura me te Whakaiti i roto i ngā Pūtau Galvanic (Ngā Pūtau Voltaic)
Ka hurihia e ngā pūtau galvanic te pūngao matū hei pūngao hiko. Ka puta noa te tauhohenga redox, ka rere ngā irahiko mā roto i te ara iahiko o waho, ka puta he iahiko.
Ko te tauira tino rongonui ko te pūtau Daniell e titoa ana i ngā irahiko konutea (Zn) me te parahi (Cu):
– Anode (waikura): Ka tukuna e te Zn ngā irahiko
\[
\text{Zn(s)} \rightarrow \text{Zn}^{2+}\text{(aq)} + 2e^-
\]
– Katote (whakaiti): Ka tangohia e ngā iona Cu²⁺ ngā irahiko
\[
\text{Cu}^{2+}\text{(aq)} + 2e^- \rightarrow \text{Cu(s)}
\]
Ka rere ngā irahiko mai i te anode (Zn) ki te cathode (Cu) mā te waea. I taua wā, hei pupuri i te kore utu i roto i te otinga, ka whakamahia he piriti tote hei tuku i ngā iona kia neke me te taurite i te utu.
Ngā āhuatanga nui o ngā pūtau galvanic:
– Tauhohenga tūpono.
– He utu kino te anode (nā te mea koinei te pūtake o ngā irahiko).
– He pai te utu o te katote.
Te Waikura me te Whakaiti i roto i ngā Pūtau Hikohiko
He rerekē ki ngā pūtau konukōre, me whai pūtake hiko o waho ngā pūtau hiko hei akiaki i ngā tauhohenga kore-ā-pūmanawa. Ka "ākina" e te iahiko ngā irahiko kia rere, ka taea ai te tauhohenga redox.
Hei tauira: te hikohiko o te wai tote, te hikohiko rānei o te wai.
Hei tauira, i roto i te whakapūtanga o te wai (me ngā irahiko tautoko), ka puta ngā mea e whai ake nei:
– Te whakaiti i te katote: ka tangohia e te wai ngā irahiko hei whakaputa hau hauwai.
\[
2H_2O + 2e^- \perematau H_2 + 2OH^-
\]
– Te waikura i te anode: ka tukuna ngā irahiko e ngā katote wai/waikura hei whakaputa hau hāora.
\[
4OH^- \rightarrow O_2 + 2H_2O + 4e^-
\]
Ngā āhuatanga nui o ngā pūtau hikohiko:
– Tauhohenga kore-ā-pūmau.
– He anode utu pai (e hono ana ki te pou pai o te pūtake hiko).
– He utu kino te katote.
Ahakoa he rerekē ngā tohu o te irahiko ina whakaritea ki te pūtau konukōre, kei te mau tonu te ture matua: ka puta te waikura i te anode, ka puta te whakaiti i te cathode.
Te Tūranga o ngā Kaihautū me ngā Kaiwhakaiti
I roto i ngā tauhohenga redox, e rua ngā "kaitākaro" matua e mōhiotia ana:
– Kaiwhakaora (kaiwhakaora): he matū e meinga ai tētahi atu matū kia waikura, kia whakaitihia ai te kaiwhakaora (ka whiwhi i ngā irahiko).
– Kaiwhakaiti (kaihoko whakaiti): he matū e whakaiti ana i tētahi atu matū, kia waikura ai te kaiwhakaiti (e tuku ana i ngā irahiko).
I roto i te pūtau o Daniell:
– He kaiwhakaiti te konutea (Zn) nā te mea ka tukuna e ia ngā irahiko.
– He matū whakahāora te ion Cu²⁺ nā te mea ka tangohia e ia ngā irahiko.
He mea nui tēnei ariā mō te matapae i te ahunga o ngā tauhohenga me te mārama he aha i taea ai e ētahi takirua matū te whakaputa i ngā ngaohiko nui ake i ētahi atu.
Te Pūmanawa Hiko me te Āhuatanga Redox
I roto i te matū hiko, ka whakaatuhia te āhua o te matū ki te whakahekenga mā tōna pūmanawa whakahekenga paerewa (E°). Ko te teitei ake o te uara E°, ko te ngāwari ake o te whakahekenga o te matū (ko te kaha ake o tōna kaha hei ākena waikura). I tetahi atu taha, ko ngā matū he iti, he kino rānei te E° ka ngāwari ake te waikura (he ākena whakaheke kaha ake).
Ko te ngaohiko o te pūtau galvanic ka taea te whakatau tata mā te whakamahi i:
\[
E^\circ_{\text{pūtau}} = E^\circ_{\text{katode}} – E^\circ_{\text{anode}}
\]
Mena he pai te tauhohenga o \(E^\circ_{\text{sel}}\), ka puta noa te tauhohenga (he pai mō ngā pūtau konukōre).
Ngā Whakamahinga o te Whakaiti-Waikura i roto i te Ao me te Ahumahi
He hononga tata ngā tukanga waikura me te whakaiti i roto i te matū hiko ki ngā mahi a te tangata. Ko ētahi o ōna whakamahinga nui ko:
1. Ngā pākahiko me ngā pūhikohiko: whakamahia ngā tauhohenga redox hei whakaputa hiko, hei tauira, ngā pākahiko kawakore, ngā pākahiko lithium-ion, me ngā pākahiko waikawa-mata.
2. Whakakikoruatanga whakarewa (whakakikoruatanga hiko): pērā i te whakakikoruatanga chrome, nickel rānei hei whakapai ake i te āhua me te ātete ki te waikura.
3. Te whakamahine i te konganuku: hei tauira, te whakamahine i te parahi mā te whakamahi i te hikohiko hei whiwhi i te konganuku kounga teitei.
4. Te tiaki i te waikura: mā ngā tikanga tiaki katote i runga i ngā paipa o raro whenua, i ngā takere kaipuke rānei, ka ārai i te waikura o te rino.
5. Pūtau wahie: ka huri i te pūngao matū o te wahie (hei tauira, te hauwai) hei hiko mā te tauhohenga redox e whakahaeretia ana.
Whakamutunga
Ko te waikura me te whakaiti te kaupapa matua o te matū hiko. Ko te waikura te tukunga o ngā irahiko, ko te whakaiti ia te whiwhinga o ngā irahiko. Ka puta tahi tonu ēnei tukanga e rua i roto i ngā tauhohenga redox, ā, koinei te pūtake mō te mahi a ngā pūtau galvanic me te electrolytic. Mā te mārama ki te wāhi e puta ai te waikura (anode) me te whakaiti (cathode), ngā mahi a ngā matū waikura me ngā matū whakaiti, me te ariā o te pūmanawa hiko, ka taea e tātou te whakamārama i ngā āhuatanga mai i te mahi a ngā pākahiko ki ngā tukanga ahumahi nui. Ehara te matū hiko i te ariā noa iho i roto i ngā pukapuka ako; ko te pūtaiao tēnei e tautoko ana i te maha o ngā hangarau hou e whakamahia ana e tātou i ia rā.
