Qhov sib txawv ntawm Cov Acid Muaj Zog thiab Cov Acid Tsis Muaj Zog
Hauv cov lus qhia txog chemistry, cov lus hais tias cov kua qaub muaj zog thiab cov kua qaub tsis muaj zog feem ntau tshwm sim thaum tham txog cov tshuaj, pH, thiab cov tshuaj tiv thaiv hauv dej. Ob qho tib si yog cov kua qaub, cov tshuaj uas tsim cov hydrogen ions (H⁺) thaum yaj hauv dej. Txawm li cas los xij, lub zog ntawm cov kua qaub tsis yog txiav txim siab los ntawm nws saj qaub npaum li cas lossis pH ntawm nws cov tshuaj qis npaum li cas. Qhov sib txawv ntawm cov kua qaub muaj zog thiab cov kua qaub tsis muaj zog yog qib ntawm ionization (dissociation) ntawm cov kua qaub hauv dej. Tsab xov xwm no yuav tham txog qhov sib txawv ntawm ob qho tib si, npog cov tswv yim, piv txwv, cov khoom, thiab lawv cov kev siv hauv lub neej txhua hnub.
Kev Txhais ntawm Acid Raws li Chemistry
Feem ntau, cov kua qaub tuaj yeem piav qhia los ntawm ntau txoj kev xav:
1. Arrhenius: Acid yog ib yam khoom uas ua rau H⁺ ntau ntxiv hauv dej.
2. Brønsted–Lowry: Cov kua qaub yog cov neeg pub proton (H⁺).
3. Lewis: Ib qho kua qaub yog ib qho uas txais tau cov electron pair.
Hauv cov ntsiab lus ntawm cov kua qaub muaj zog thiab cov kua qaub tsis muaj zog, kev sib tham feem ntau siv cov kev xav ntawm Arrhenius thiab Brønsted-Lowry, vim tias ob qho tib si muaj feem cuam tshuam ncaj qha rau kev tsim cov H⁺ / H₃O⁺ ions hauv cov kua.
Cov kua qaub muaj zog yog dab tsi?
Cov kua qaub muaj zog yog cov kua qaub uas ionizes tag nrho (lossis yuav luag tag nrho) hauv dej. Qhov no txhais tau tias thaum cov kua qaub muaj zog yaj, feem ntau ntawm nws cov molecules tawg ua lawv cov ions sib xyaw, feem ntau yog H⁺ ions (uas hauv dej tsim H₃O⁺). Vim tias ionization yuav luag tiav 100%, qhov concentration ntawm H⁺ tsim yog siab heev.
Piv txwv li, hydrochloric acid (HCl) hauv dej yuav ionize yuav luag tag nrho:
HCl (aq) → H⁺ (aq) + Cl⁻ (aq)
Vim tias lawv tsim ntau cov ions, cov kua qaub muaj zog feem ntau yog cov electrolytes muaj zog, uas yog, cov kua uas tuaj yeem coj hluav taws xob zoo.
Piv txwv ntawm Cov Acids Muaj Zog
Qee cov kua qaub uas muaj zog feem ntau yog:
- Hydrochloric acid (HCl)
- Hydrobromic acid (HBr)
- Hydroxydioxide (HI)
- Nitric acid (HNO₃)
– Sulfuric acid (H₂SO₄) (ionization muaj zog hauv thawj theem)
- Perchloric acid (HClO₄)
Dab tsi yog Weak Acid?
Cov kua qaub tsis muaj zog yog cov kua qaub uas ib feem ionizes hauv dej. Yog li, tsuas yog qee cov molecule kua qaub tso tawm cov protons (H⁺), thaum cov seem tseem yog cov molecule kua qaub sib koom ua ke. Vim tias lawv tsim cov ions tsawg dua li cov kua qaub muaj zog, cov kua qaub tsis muaj zog feem ntau yog cov electrolytes tsis muaj zog.
Piv txwv li, acetic acid (CH₃COOH), lub ntsiab tivthaiv ntawm vinegar, yog ib feem ionized:
CH₃COOH (aq) ⇌ H⁺ (aq) + CH₃COO⁻ (aq)
Tus xub rov qab thiab tawm (⇌) qhia txog qhov muaj qhov sib npaug, vim tias qhov kev sib xyaw ua ke ionization tshwm sim hauv ob qho kev qhia: qee qhov dissociate, qee qhov recombine.
Piv txwv ntawm Cov Acids Uas Tsis Muaj Zog
Nov yog qee cov kua qaub tsis muaj zog uas feem ntau pom:
- Acetic acid (CH₃COOH)
- Cov pa roj carbonic (H₂CO₃)
- Phosphoric acid (H₃PO₄)
- Hydrofluoric acid (HF)
- Citric acid (C₆H₈O₇)
- Formic acid (HCOOH)
Qhov Txawv Tseem Ceeb Ntawm Cov Acids Muaj Zog Thiab Cov Acids Tsis Muaj Zog
1. Qib ntawm Ionization
– Cov kua qaub muaj zog: ionizes yuav luag 100% hauv dej.
– Cov kua qaub tsis muaj zog: ib feem ionized, tsim kom muaj qhov sib npaug.
Qhov no yog qhov tseem ceeb ntawm qhov sib txawv. Lub zog ntawm cov kua qaub tsis yog txiav txim los ntawm qhov concentration ntawm cov tshuaj, tab sis yog los ntawm qhov kev nyiam ntawm cov molecules kua qaub kom tso H⁺.
2. Tus Nqi Ka (Acid Dissociation Constant)
Qhov acidity tuaj yeem ntsuas los ntawm Ka, uas yog qhov sib npaug tas mus li rau cov tshuaj tiv thaiv acid ionization.
- Cov kua qaub muaj zog muaj Ka loj heev (lossis pKa me heev), vim tias lawv cov ionization yuav luag tiav lawm.
- Cov kua qaub tsis muaj zog muaj Ka me me (pKa loj dua), vim tias tsuas yog qee qhov ntawm lawv thiaj li ionize.
Qhov loj dua Ka, qhov muaj zog dua cov kua qaub.
3. pH ntawm Cov Tshuaj ntawm Tib Qhov Kev Ntsuas
Ntawm tib qho concentration (piv txwv li 0,1 M):
– Cov kua qaub muaj zog tsim ntau H⁺ → pH qis dua.
– Cov kua qaub tsis muaj zog tsim H⁺ tsawg dua → pH siab dua.
Txawm li cas los xij, nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias pH kuj raug cuam tshuam los ntawm qhov concentration. Cov kua qaub qaug zog uas muaj zog heev tuaj yeem muaj pH qis dua li cov kua qaub muaj zog uas yaj heev. Yog li ntawd, kev sib piv pH yuav tsum tau ua ntawm tib qhov concentration kom ncaj ncees.
4. Kev Ua Hluav Taws Xob
- Cov kua qaub muaj zog: coj hluav taws xob tau zoo vim nws muaj ntau cov ions dawb.
- Cov kua qaub tsis muaj zog: coj hluav taws xob tsis zoo vim nws muaj tsawg dua ions.
Qhov no yog qhov laj thawj vim li cas hauv kev ua haujlwm tiag tiag, cov kua qaub muaj zog tuaj yeem ua rau lub teeb qhia ci dua li cov kua qaub tsis muaj zog ntawm tib qho concentration.
5. Kev ua haujlwm tsis zoo hauv ntau yam kev ua haujlwm tsis zoo
Feem ntau, cov kua qaub muaj zog ua rau muaj kev cuam tshuam ntau dua nyob rau hauv ntau yam mob vim muaj H⁺ ntau dua. Txawm li cas los xij, kev cuam tshuam kuj tseem txiav txim siab los ntawm hom kev cuam tshuam, cov kuab tshuaj, qhov kub, thiab cov tshuaj reactants. Piv txwv li, hauv kev cuam tshuam nrog cov hlau, ob qho tib si kua qaub muaj zog thiab tsis muaj zog tuaj yeem tsim cov roj hydrogen, tab sis ntawm cov nqi sib txawv.
6. Cov Khoom Uas Ua Rau Kub Thiab Kev Nyab Xeeb
Cov kua qaub muaj zog feem ntau suav tias muaj kev phom sij ntau dua vim tias lawv cov pH feem ntau qis heev. Txawm li cas los xij, tsis yog txhua cov kua qaub tsis muaj zog muaj kev nyab xeeb. Qee cov kua qaub tsis muaj zog tseem tuaj yeem muaj kev phom sij, tshwj xeeb tshaj yog tias lawv muaj cov kua qaub ntau lossis muaj cov khoom lom.
Piv txwv:
- HF (hydrofluoric acid) yog cais ua cov kua qaub tsis muaj zog hauv kev ionization, tab sis nws txaus ntshai heev vim nws tuaj yeem nkag mus rau hauv cov ntaub so ntswg thiab khi calcium hauv lub cev.
- Cov kua qaub muaj zog xws li HCl uas muaj concentrated kuj yog cov corrosive heev thiab tuaj yeem ua rau kub hnyiab.
Yog li ntawd, "tsis muaj zog" tsis txhais hais tias "tsis muaj teeb meem".
Kev Siv Cov Acids Muaj Zog thiab Cov Acids Tsis Muaj Zog hauv Lub Neej
Cov kua qaub muaj zog hauv kev lag luam
Cov kua qaub muaj zog feem ntau siv rau:
– Kev tsim cov chiv (piv txwv li H₂SO₄ thiab HNO₃)
- Tshuaj ntxuav xeb thiab nplai (HCl)
- Kev ua hlau (pickling)
- Cov khoom siv raw rau qee cov tshuaj syntheses
Vim lawv qhov xwm txheej ua haujlwm thiab muaj peev xwm muab H⁺ ntau ntau, cov kua qaub muaj zog zoo rau cov txheej txheem kev lag luam loj, txawm hais tias lawv xav tau kev ceev faj kev nyab xeeb nruj.
Cov kua qaub tsis muaj zog hauv cov khoom noj thiab biology
Cov kua qaub tsis muaj zog feem ntau pom muaj nyob rau hauv:
- Khoom noj thiab dej haus (citric acid hauv cov txiv hmab txiv ntoo citrus, acetic acid hauv vinegar)
- Lub cev tiv thaiv kab mob hauv lub cev
- Cov txheej txheem fermentation thiab kev khaws cia
Cov kua qaub tsis muaj zog feem ntau siv ua cov tshuaj tswj cov saj, cov tshuaj tiv thaiv, thiab cov khoom ntawm cov txheej txheem buffer vim tias lawv qhov ionization ib nrab ua rau pH hloov pauv yooj yim dua.
Xaus
Qhov txawv ntawm cov kua qaub muaj zog thiab cov kua qaub tsis muaj zog feem ntau yog nyob rau hauv qib ntawm ionization hauv dej. Cov kua qaub muaj zog ionize yuav luag tag nrho, tsim ntau H⁺ ions, muaj Ka siab, pH qis dua ntawm tib qhov concentration, thiab conductivity siab dua. Qhov sib piv, cov kua qaub tsis muaj zog ionize tsuas yog ib feem, tsim kom muaj qhov sib npaug, muaj Ka qis dua, thiab muaj conductivity qis dua. Txawm li cas los xij, lo lus "tsis muaj zog" tsis txhais tau tias muaj kev nyab xeeb, vim tias qee cov kua qaub tsis muaj zog tuaj yeem ua rau muaj kev phom sij nyob ntawm lawv qhov concentration thiab cov khoom siv tshuaj lom neeg.
Kev nkag siab txog qhov txawv no tseem ceeb tsis yog rau kev xeem chemistry xwb, tab sis kuj tseem ceeb rau kev nkag siab txog tej yam tshwm sim txhua hnub, los ntawm qhov saj qaub ntawm cov zaub mov mus rau kev siv cov tshuaj lom neeg hauv chaw soj nstuam thiab kev lag luam.
