Pehea e hoʻoholo ai i nā helu oxidation
ʻO ka hoʻomaopopo ʻana i nā helu oxidation (a i ʻole nā kūlana oxidation) he manaʻo koʻikoʻi ia i ka kemika e kōkua iā mākou e hoʻomaopopo i nā hopena kemika, ʻoiai nā hopena redox. ʻO ka helu oxidation ka helu o nā electrons e pono e hoʻohui ʻia a wehe ʻia paha mai kahi ʻātoma e hoʻololi iā ia i kona kūlana kumu. Ma kēia ʻatikala, e ʻimi hohonu mākou pehea e hoʻoholo ai i ka helu oxidation o kahi mea i loko o kahi hui kemika.
Nā Kumu o ka Helu ʻOkika
Hiki ke manaʻo ʻia nā helu oxidation he mea hana makemakika kūhelu e wehewehe ana i ka hoʻolaha ʻana o nā electrons i loko o kahi mole a i ʻole ion. ʻOiai ʻaʻole hōʻike mau nā helu oxidation i ka uku uila maoli o nā ʻātoma i loko o ka mole, hoʻomaʻalahi lākou i ka nānā ʻana i nā kemika.
Eia kekahi mau lula kumu no ka hoʻoholo ʻana i nā helu oxidation:
1. ʻO ka helu oxidation o kahi mea ma ke ʻano o kahi molekala mea (homonuclear) he ʻole mau. Eia kekahi laʻana:
– O₂ (dioxygen) -> ʻO kona helu oxidation he 0
– N₂ (dinitrogen) -> ʻO kona helu oxidation he 0
2. Ua like ka helu oxidation no kahi ion monatomic me ka uku o ka ion.
– Na⁺ -> ʻO kona helu oxidation he +1
– Cl⁻ -> ʻO kona helu oxidation he -1
3. ʻO ka helu oxidation o ka hydrogen he +1 ke hoʻopaʻa ʻia me kahi mea ʻole-metala a -1 ke hoʻopaʻa ʻia me kahi metala i loko o kahi hydride. Eia kekahi laʻana:
– H₂O -> ʻO ka helu oxidation o ka hydrogen he +1
– NaH -> ʻO ka helu oxidation o ka hydrogen he -1
4. ʻO ka helu oxidation o ka oxygen he -2 ma ka hapa nui o nā hui, akā aia nā ʻokoʻa e like me nā peroxides kahi i loaʻa ai ka helu oxidation o ka oxygen he -1.
– H₂O -> ʻO ka helu oxidation o ka oxygen he -2
– H₂O₂ (hydrogen peroxide) -> ʻO ka helu oxidation o ka oxygen he -1
5. ʻO ka helu oxidation o nā halogens (F, Cl, Br, I) i loko o nā hui he -1 maʻamau, koe wale nō ka hui pū ʻana me ka oxygen a i ʻole nā halogens ʻē aʻe kahi e hiki ai ke ʻokoʻa.
Nā ʻanuʻu e hoʻoholo ai i nā helu Oxidation
No ka hoʻoholo ʻana i ka helu oxidation o kahi mea i loko o kahi hui, hiki iā mākou ke hahai i kēia mau hana:
KaʻAnuʻu Hana 1: E kākau i ke ʻAno/Haʻilula Molekala o ka Hui
E hoʻomaka ma ke kākau ʻana i ke ʻano molekala a i ʻole ke ʻano o ka hui. No ka laʻana, no H₂SO₄ (waikawa sulfuric).
KaʻAnuʻu Hana 2: E hoʻoholo i ka Helu Oxidation o nā Elements ma muli o nā Rula
– No H₂SO₄, ʻike mākou he +1 ka helu oxidation o ka hydrogen a he -2 ka helu oxygen.
– Hydrogen (H): +1 (2 mau ʻātoma H, +2 huina)
– Oxygen (O): -2 (4 mau ʻātoma O, -8 huina)
KaʻAnuʻu Hana 3: E hoʻoholo i ka Helu Oxidation o ka Element i ʻike ʻole ʻia
Inā makemake ʻia ka hui e kūlike ʻole a inā paha e hana ana mākou i nā ion, pono mākou e hōʻoia i ka waiwai holoʻokoʻa o ka helu oxidation he ʻole no nā hui kūlike ʻole a i ʻole like me ka uku ionic no nā ion.
– He hui kūlike ʻole ka waikawa sulfuric (H₂SO₄). No laila, pono ka huina o nā kūlana oxidation he ʻole.
– Loaʻa iā mākou nā helu oxidation no H (+1) a me O (-2), no laila e ʻike ai i ka helu oxidation o ka sulfur (S), hoʻohana mākou i ka hoohalike:
\[
2(+1) + S + 4(-2) = 0
\]
\[
2 + S – 8 = 0
\]
\[
S – 6 = 0
\]
\[
S = +6
\]
No laila, ʻo ka helu oxidation no ka sulfur ma H₂SO₄ he +6.
KaʻAnuʻu Hana 4: Hōʻoia
E hōʻoia i ka like ʻana o ka huina o nā helu oxidation me 0 no nā molekala kūlike ʻole a i ʻole e pili ana i ka uku ionic inā mākou e hana nei me nā ions.
ʻO kekahi laʻana o ka hoʻoholo ʻana i nā helu Oxidation
Laʻana 1: Potassium Permanganate (KMnO₄)
No kēia hui ʻana, hahai mākou i nā lula ma luna:
– Potasiuma (K): ʻO ka maʻamau +1
– ʻOkikene (O): -2
Ua ʻike mākou he kūlike ʻole kēia mole, e hopena ana i ka hoohalike:
\[
1(+1) + Mn + 4(-2) = 0
\]
\[
1 + Mn – 8 = 0
\]
\[
Mn – 7 = 0
\]
\[
Mn = +7
\]
No laila, ʻo ka helu oxidation o Mn ma KMnO₄ he +7.
Laʻana 2: Ammonium Nitrate (NH₄NO₃)
No kēia hui ʻana, ʻelua ʻāpana kā mākou: NH₄⁺ a me NO₃⁻.
– NH₄⁺:
– ʻAilakona (H): +1
– No laila no ka naikokene (N) ma NH₄⁺:
\[
N + 4(+1) = +1
\]
\[
N + 4 = +1
\]
\[
N = -3
\]
– ʻAʻOLE₃⁻:
– ʻOkikene (O): -2
– Naikokene (N) i loko o NO₃⁻:
\[
N + 3(-2) = -1
\]
\[
N – 6 = -1
\]
\[
N = +5
\]
Kekahi mau ʻokoʻa a me nā mea kūikawā
Aia kekahi mau ʻokoʻa i ke kānāwai maʻamau e hoʻomanaʻo:
1. ʻOkikene i loko o ka Peroxide:
– I loko o H₂O₂ a i ʻole Na₂O₂, ʻo ka helu oxidation o ka oxygen he -1, ʻaʻole -2.
2. Nā ʻElemene me nā Helu ʻOkika He nui:
– ʻOkoʻa pinepine nā helu oxidation o nā mea e like me ka phosphorus (P), sulfur (S), a me nā metala hoʻololi i nā hui like ʻole. No ka laʻana, hiki i ka hao (Fe) ke loaʻa kahi helu oxidation o +2 a i ʻole +3.
3. He +2 mau nā metala honua alkali a he +1 mau nā metala alkali.
Ka hopena
ʻO ka hoʻoholo ʻana i nā helu oxidation he mākaukau koʻikoʻi a koʻikoʻi hoʻi i ka kemika, ʻoiai no ka hoʻomaopopo ʻana i nā hopena redox a me nā ʻano hopena kemika like ʻole. Ma ka hahai ʻana i nā lula a me nā ʻanuʻu i luna, e hiki iā ʻoe ke hoʻoholo pololei i nā helu oxidation i nā ʻano hui kemika like ʻole. E hoʻomaʻamaʻa i ka hoʻoholo ʻana i nā helu oxidation me nā laʻana like ʻole o nā hui e hoʻoikaika i kou ʻike.
