Te Kaha me te pH o te Waikawa-Pūtake
Ko ngā waikawa me ngā kawakore he ariā matua e rua i roto i te matū, he mea nui ki ngā tauhohenga matū me ngā tukanga ora. He mea nui te mārama ki te kaha o ngā waikawa me ngā kawakore, me tō rātou ine, i roto i ngā horopaki taiwhanga me ngā mahi o ia rā. Ka tūhuratia e tēnei tuhinga te kaha o ngā waikawa me ngā kawakore, te ariā o te pH, me te āhua o tō rāua hononga me te whakamahinga.
Te Whakamāramatanga o ngā Waikawa me ngā Kawenga
I ngā kupu māmā noa iho, ko te waikawa he matū e kaha ana ki te tuku i ngā iona hauwai (H⁺) ki roto i te wairewa, ko te kawa he matū e kaha ana ki te tango i ēnei iona hauwai. E ahu mai ana tēnei whakamāramatanga i te ariā Bronsted-Lowry. Waihoki, e ai ki te ariā Arrhenius, ko te waikawa he matū e whakaputa ana i ngā iona hauwainium (H₃O⁺) i roto i te wai, ā, ko te kawa he matū e whakaputa ana i ngā iona hauwai (OH⁻) i roto i te wai.
Te Kaha o ngā Waikawa me ngā Kawenga
Kaha Waikawa
Ko te kaha o te waikawa e pā ana ki tōna kaha ki te tuku i ngā iona hauwai (H⁺) ki roto i te wairewa. Ka tata wehea katoatia ngā waikawa kaha i roto i te wai, arā, ka tukuna e te nuinga o ngā ngota waikawa te H⁺. Ko ngā tauira o ngā waikawa kaha ko te waikawa hauwaiora (HCl), te waikawa whanariki (H₂SO₄), me te waikawa hauota (HNO₃).
He rerekē, ka wehea noatia ngā waikawa ngoikore i roto i te wairewa. Ko ētahi tauira o ngā waikawa ngoikore ko te waikawa acetic (CH₃COOH) me te waikawa waro (H₂CO₃). Ko te nui o te wehenga o te waikawa ngoikore ka whakaatuhia i roto i te pūmau wehenga waikawa (Ka).
Te Kaha o te Tūāpapa
Pērā i ngā waikawa, ka taea te whakarōpū i ngā turanga hei turanga kaha, hei turanga ngoikore rānei. Ko ngā turanga kaha ko ērā e tata ana ki te whakakōkī katoa i roto i te wairewa. Ko ngā tauira o ngā turanga kaha ko te hauwai konutai (NaOH) me te hauwai pāhare pākawa (KOH).
Ko ngā turanga ngoikore ia, ka whaka-ionitihia noa iho i roto i te wairewa. Ko ētahi tauira o ngā turanga ngoikore ko te haukini (NH₃). Ka inehia hoki te kaha o te turanga i runga i te pūmau wehenga turanga (Kb).
ariā pH
Ko te pH he ine i te waikawa, te kawakore rānei o tētahi otinga. He tauine logarithm tēnei mai i te 0 ki te 14. Ko te whakamāramatanga o tēnei tauine ko:
\[
\kāhua{pH} = -\log[H⁺]
\]
Ko [H⁺] te kukū o ngā iona hauwai i roto i te wairewa. Ko te pH o te 7 e kiia ana he kūpapa (pērā i te wai parakore), ko te pH i raro i te 7 he waikawa, ā, ko te pH i runga ake i te 7 he taketake.
Te whanaungatanga i waenga i te kaha me te pH
He nui te pānga o te kaha o te waikawa, o te kawa rānei ki te pH o te otinga. Mō ngā waikawa kaha, nā te mea ka wehea katoatia, ka taea te tatau tika i te pH mai i tō rātou kukū molar. Hei tauira, ko te pH o te otinga HCl 0.1 M ko:
\[
\text{pH} = -\log[0.1] = 1
\]
Mō ngā waikawa ngoikore, kāore i oti te nui o te wehenga, nō reira kāore e taea te tatau tika i te pH mai i te kukū molar tuatahi. Engari, ka whakamahia e mātou te whārite Ka hei whakatau i te kukū katote hauwai i te taurite.
Tauira: Mō te waikawa acetic (CH₃COOH) me te Ka = 1.8 x 10⁻⁵, ka taea e tātou te tatau i te pH o te otinga 0.1 M mā te whakamahi i te whārite:
\[
Ka = \frac{[H⁺][A⁻]}{[HA]}
\]
Ki te whakaaro ko [H⁺] me [A⁻] ko x, ā, ko [HA] ≈ 0.1 – x. Mai i konei, whakaotihia te x, arā, ko [H⁺], kātahi ka tatau i te pH.
Ngā Taupānga i roto i te Oranga o Ia Rā
He whānuitia ngā whakamahinga o te mārama ki te kaha o ngā waikawa me ngā kawakore me te pH i roto i te oranga o ia rā:
1. Ahumahi Kai me te Inu
He mea nui te pH i roto i te tukatuka kai me te inu. Hei tauira, he mea tika te pH tika mō te whakapūkara o te pia me te waina. Ka whakamahia hoki hei pupuri i te kounga me te haumaru o ngā hua kai.
2. Te Taurite o te Hauora me te Tinana
E hiahiatia ana e te tinana tangata he pH pumau puta noa i ōna pūnaha maha. Hei tauira, ko te pH o te toto tangata he tata ki te 7.4. Ka taea e ngā panonitanga iti o te pH o te toto te whakararu i te hauora.
3. Ahuwhenua
Ko te oneone me te pH tika te mea nui mō te angitu o te mahi ahuwhenua. Ka pā te pH o te oneone ki te wātea o ngā matūkai ki ngā tipu. Nō reira, he maha ngā wā ka whakatikatikahia e ngā kaimahi pāmu te pH o te oneone mā te tāpiri i te raima hei whakanui ake, te whanariki rānei hei whakaiti.
4. Te Maimoatanga Wai
He tohu nui te pH o te wai mō te kounga o te wai. Ka pā te whakahaere i te pH o te wai ki ngā āhuatanga maha, tae atu ki te reka, te tae, me te patu huakita. He maha ngā wā ka tāpirihia ngā waikawa, ngā kawakore rānei ki te wai hei whakatutuki i te pH e hiahiatia ana i roto i ngā tukanga maimoatanga wai.
5. Te Whakahaere i te Parahanga
He auau te aroturuki a ngā umanga i te pH o ā rātou wai para kia tutuki ai ngā paerewa taiao, kia whakaitihia ai hoki te parahanga. I mua i te tukunga o te wai para ki te taiao, ka whakakorea te pH mā te tāpiri waikawa, kawa rānei kia tata ake ai te pH ki te kūpapa.
Ngā Āhuatanga e Pā Ana ki te Kaha o ngā Waikawa me ngā Kawenga
He maha ngā āhuatanga e pā ana ki te kaha o ngā waikawa me ngā kawakore, arā:
1. Hanganga Ngota
He mea nui te hanganga ngota hei whakatau i te kaha o te waikawa, o te turanga rānei. Ko ngā waikawa he kaha te hononga i waenga i ngā ngota hauwai me te ngota here ka ngoikore nā te mea he uaua ki te tuku i ngā katote hauwai. I tetahi atu taha, ko ngā waikawa he ngoikore te hononga ka kaha.
2. Te kaha hikohiko
He hononga pai te irahiko-kore o ngā ngota honohono ki te kaha o te waikawa. Ko ngā ngota he nui ngā irahiko-kore ka kukume i ngā irahiko, ā, ka māmā ake te tuku i ngā irahiko hauwai.
3. Whakarewa
Ka pāngia hoki te kaha o ngā waikawa me ngā kawakore e ngā whakarewa. Hei tauira, he whakarewa pai te wai mō ngā waikawa me ngā kawakore nā tōna kaha polarity.
4. Pānga Whakaoho
Ka pā anō hoki te pānga whakaaweawe o ngā rōpū ngota rerekē i roto i te ngota ki tōna kaha. Ko ngā rōpū tango-irahiko (pērā i ngā halogen) i roto i te ngota ka whakanui ake i te waikawa.
Whakamutunga
He mea nui te mōhio ki ngā waikawa me ngā turanga, tae atu ki tō rātou kaha me te pH, ki te mārama ki ngā tauhohenga matū maha me ngā whakamahinga i roto i ngā momo mara. Ko te kaha o ngā waikawa me ngā turanga ka whakatauhia e tō rātou kaha ki te tuku, ki te tango rānei i ngā iona hauwai, e pā tika ana ki te pH o te otinga. He mea āwhina te mārama ki tēnei mōhiotanga ehara i te mea i roto i ngā mara pūtaiao anake engari i roto hoki i te oranga o ia rā me ngā momo ahumahi. Mā tēnei māramatanga ka tuwhera te huarahi mō ngā whakamahinga whānui ake, ā, ka āwhina i te whakatinanatanga o ngā tikanga tika i roto i te whānuitanga o ngā tukanga, mai i te umanga kai ki te maimoatanga wai me te hauora. Nō reira, ko te mōhio ki tēnei mea te mea nui ki te ahunga whakamua hangarau me te whakapai ake i te kounga o te oranga.
