Nā nīnau hoʻohālike e kūkākūkā ana i nā Electrolytes ikaika, nā Electrolytes nāwaliwali, a me nā Non-electrolytes
He manaʻo koʻikoʻi nā electrolytes i ka kemika, ʻoiai hoʻi i ke aʻo ʻana i nā hopena e pili ana i nā hopena. ʻO nā electrolytes nā hui, ke hoʻoheheʻe ʻia i ka wai, e hana i nā ions e hiki ai i ka hopena ke alakaʻi i ka uila. Ma muli o ko lākou hiki ke hoʻokaʻawale i nā ions, ua māhele ʻia nā electrolytes i ʻekolu mau māhele: electrolytes ikaika, electrolytes nāwaliwali, a me nā non-electrolytes. E kūkākūkā kēia ʻatikala i nā pilikia hoʻohālike like ʻole e pili ana i kēia mau ʻano electrolytes ʻekolu, me nā wehewehe maʻalahi e hoʻomaopopo.
ʻElectrolyte ikaika
ʻO nā electrolytes ikaika he mau hui e ionize piha i loko o ka wai. ʻO ke ʻano kēia, i ka wā e hoʻoheheʻe ʻia ai kahi electrolyte ikaika i loko o ka wai, aneane pau nā molekala a pau i loko o nā ions. ʻO nā hiʻohiʻona maʻamau o nā electrolytes ikaika e komo pū me nā paʻakai e like me ka sodium chloride (NaCl), nā waikawa ikaika e like me ka hydrochloric acid (HCl), a me nā kumu ikaika e like me ka sodium hydroxide (NaOH).
Nīnau 1:
Pehea e helu ai i ka molarity o nā ions i loko o kahi hopena HCl 0,1 M?
Kūkākūkā:
He waikawa ikaika ʻo HCl e hoʻokaʻawale loa i ka wai e like me ke ʻano hoʻohālikelike:
\[ \kikokikona{HCl} \rightarrow \kikokikona{H}^+ + \kikokikona{Cl}^- \]
ʻOiai he electrolyte ikaika ʻo HCl, hiki iā mākou ke lawe i ka nui mua o HCl (0,1 M) ma ke ʻano he nui o nā H+ a me Cl- ions i hoʻokumu ʻia. No laila, i loko o kahi hopena 0,1 M HCl:
[\(\text{H}^+\)] = 0,1 M
[\(\text{Cl}^-\)] = 0,1 M
Electrolyte nāwaliwali
Hoʻohui hapa wale nā electrolytes nāwaliwali i ka hopena. ʻO ke ʻano kēia he hapa liʻiliʻi wale nō o nā molekala o kahi electrolyte nāwaliwali e hana i nā ions ke hoʻoheheʻe ʻia i loko o ka wai. ʻO nā hiʻohiʻona o nā electrolytes nāwaliwali e komo pū me nā waikawa nāwaliwali e like me ka waikawa acetic (CH3COOH) a me nā kumu nāwaliwali e like me ka ammonia (NH3).
Nīnau 2:
E hoʻoholo i ke kekelē o ka ionization a me ka nui o ka ion ma 0,1 M CH3COOH. ʻO ke kūpaʻa dissociation acid (\(K_a\)) no CH3COOH he 1,8 × 10^-5.
Kūkākūkā:
Hiki ke kākau ʻia ka hopena dissociation o CH3COOH i loko o ka wai penei:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]
Ua wehewehe ʻia ke kekelē o ka dissociation (\(\alpha\)) ʻo ia ka hapa o ka waikawa e hoʻokaʻawale i nā ions. Ma ka hoʻohana ʻana i ka waiwai o \(K_a\), hiki iā mākou ke kākau i ka pilina ma lalo nei no kahi hopena 0,1 M CH3COOH:
\[ K_a = [\text{CH}_3\text{COO}^-][\text{H}^+] / [\text{CH}_3\text{COOH}] \]
ʻOiai he hapa ka ionization o CH3COOH, ʻo ka nui o nā ions i hoʻokumu ʻia ʻo cα, kahi ʻo c ka nui mua o CH3COOH (0,1 M). A laila lilo ka hoohalike:
\[ 1,8 \times 10^{-5} = \frac{(0,1\alpha)(0,1\alpha)}{0,1(1-\alpha)} \]
E hoʻomaʻalahi i:
\[ 1,8 \times 10^{-5} = \frac{0,01\alpha^2}{0,1 – 0,1\alpha} \]
Manaʻo ʻia he liʻiliʻi ʻo α a hiki iā mākou ke hoʻowahāwahā iā α i loko o ka denominator:
\[ 1,8 \times 10^{-5} \approx 0,01\alpha^2 / 0,1 \]
\[ 1,8 \times 10^{-5} \approx \alpha^2 \]
\[ \alpha \approx \sqrt{1,8 \times 10^{-5}} \]
\[ \alpha \approx 4,24 \times 10^{-3} \]
No laila, ʻo ke kekelē o ka ionization he 4,24 × 10^-3 a i ʻole 0,424%.
ʻO ka nui o nā ion H+ a me CH3COO- i loko o ka hopena:
\[ [\text{H}^+] = 0,1 \times 4,24 \times 10^{-3} \approx 4,24 \times 10^{-4} \]
\[ [\text{CH}_3\text{COO}^-] = 0,1 \times 4,24 \times 10^{-3} \approx 4,24 \times 10^{-4} \]
Nā mea ʻaʻole electrolytes
ʻO nā non-electrolytes nā hui i ʻole e ionize i loko o ka wai. ʻO ke ʻano kēia, ʻaʻole hana nā wai non-electrolyte i nā ions, a no laila ʻaʻole hiki ke alakaʻi i ka uila. ʻO nā hiʻohiʻona o nā non-electrolytes e komo pū me ke kō (sucrose), urea, a me ka waiʻona.
Nīnau 3:
No ke aha i alakaʻi ʻole ai ka uila i kahi hopena ethanol 0,1 M (C2H5OH)?
Kūkākūkā:
He non-electrolyte ka hopena ethanol. ʻAʻole e hoʻokaʻawale ʻia ka ethanol i loko o nā ion ke hoʻoheheʻe ʻia i loko o ka wai. Noho paʻa ke ʻano molekala o ka ethanol i loko o ka hopena wai. Ma muli o ka nele o nā ion i loko o ka hopena, ʻaʻole hiki i ka ethanol ke alakaʻi i ka uila. No laila, ʻoiai ua maʻalahi ka hoʻoheheʻe ʻia o ka ethanol i loko o ka wai, no ka mea, ʻaʻohe ion i hoʻokumu ʻia, ʻaʻole hiki i nā hopena ethanol ke alakaʻi i ka uila ʻoiai ma kekahi ʻano, me 0,1 M.
Ka hopena
ʻO ka hoʻomaopopo ʻana i nā ʻano o nā electrolytes ikaika, nā electrolytes nāwaliwali, a me nā non-electrolytes he kahua koʻikoʻi ia i ka kemika hoʻonā. Hoʻohui piha nā electrolytes ikaika i ka wai a no laila e alakaʻi maikaʻi i ka uila, ʻoiai ʻo nā electrolytes nāwaliwali e ionize hapa wale nō, e hōʻike ana i ka conductivity uila haʻahaʻa. ʻO nā non-electrolytes, ma ka ʻaoʻao ʻē aʻe, ʻaʻole ionize iki a no laila ʻaʻole hiki ke alakaʻi i ka uila. ʻO ka hoʻomaopopo ʻana i kēia manaʻo e kōkua i nā haumāna e ʻike i nā hui e pili ana i kā lākou ʻano i loko o ka hoʻonā a pane pololei i nā nīnau pili.
