Cov Kev daws teeb meem tsis muaj zog: Nkag siab txog lawv cov haujlwm thiab kev siv hauv lub neej txhua hnub
Pendahuluuan
Cov tshuaj buffer yog cov khoom tseem ceeb ntawm chemistry, ua lub luag haujlwm tseem ceeb hauv kev tshawb fawb hauv chav kuaj thiab kev siv txhua hnub. Cov tshuaj buffer tswj tau pH ruaj khov hauv ib lub cev, txawm tias thaum ntxiv cov kua qaub lossis cov hauv paus. Hauv tsab xov xwm no, peb yuav ua qhov kev tshuaj xyuas tob txog cov ntsiab cai ntawm cov tshuaj buffer, lawv cov txheej txheem ua haujlwm, cov hom tshuaj buffer, thiab lawv cov ntawv thov hauv ntau qhov chaw.
Cov Ntsiab Cai Tseem Ceeb ntawm Buffer Solutions
Ib qho tshuaj buffer muaj cov kua qaub tsis muaj zog thiab nws cov conjugate base lossis cov weak base thiab nws cov conjugate acid. Lub hauv paus ntsiab lus ntawm cov tshuaj buffer yog nws lub peev xwm los neutralize cov acid lossis base ntxiv rau hauv lub system, yog li ntawd pH ntawm cov tshuaj tseem ruaj khov hauv qee qhov kev txwv.
Cov Tshuaj Tiv Thaiv Acid-Base hauv Buffer Solutions
Yuav kom nkag siab txog seb cov tshuaj buffer ua haujlwm li cas, peb yuav tsum saib ob hom kev tshuaj tiv thaiv: cov tshuaj tiv thaiv acid ntxiv thiab cov tshuaj tiv thaiv base ntxiv.
1. Ntxiv Acid (H⁺):
- Cov kua qaub tsis muaj zog hauv cov tshuaj buffer yuav tawg ib nrab thiab tsim cov H⁺ ions thiab cov conjugate base.
– Yog tias muaj kua qaub ntxiv (ntxiv H⁺), lub hauv paus sib xyaw ntawm cov kua qaub tsis muaj zog yuav cuam tshuam nrog cov H⁺ ions ntau dhau los ua cov kua qaub tsis muaj zog ntxiv, yog li ua rau cov H⁺ ntau dhau tsis muaj zog thiab ua kom pH ruaj khov.
2. Ntxiv ntawm Base (OH⁻):
– Thaum ntxiv ib lub hauv paus (ntxiv OH⁻), cov OH⁻ ions yuav ua rau cov H⁺ ions uas twb muaj lawm, ua dej.
– Tom qab ntawd, cov kua qaub tsis muaj zog yuav tawg ntxiv los hloov cov H⁺ ions uas ploj lawm, kom pH tseem ruaj khov.
Muaj Peev Xwm Tsis Muaj
Lub peev xwm ntawm cov buffer yog qhov ntsuas seb muaj pes tsawg acid lossis base uas tuaj yeem ntxiv rau hauv cov tshuaj buffer ua ntej muaj kev hloov pauv tseem ceeb hauv pH. Lub peev xwm no nyob ntawm tag nrho cov concentration ntawm cov khoom buffer (cov acid tsis muaj zog thiab nws cov conjugate base).
Qhov ntau ntawm cov pH tsis txaus
Qhov pH uas cov tshuaj buffer muaj txiaj ntsig zoo tshaj plaws feem ntau hu ua "buffer zone." Qhov no feem ntau yog kwv yees li ib chav pH qis dua pKa ntawm cov kua qaub tsis muaj zog uas siv rau hauv cov tshuaj buffer. Piv txwv li, yog tias cov kua qaub tsis muaj zog muaj pKa ntawm 4,7, cov tshuaj buffer muaj txiaj ntsig zoo hauv pH ntau ntawm 3,7 txog 5,7.
Hom Kev daws teeb meem Buffer
Cov tshuaj buffer raug faib ua pawg raws li hom acid thiab base uas lawv muaj. Nov yog ob hom tshuaj buffer tseem ceeb, nrog rau cov piv txwv thiab lawv siv:
1. Acid Buffer:
- Cov Cheebtsam: Cov kua qaub tsis muaj zog thiab nws cov hauv paus sib xyaw.
– Piv txwv li: Cov kua Acetate uas muaj acetic acid (CH₃COOH) thiab sodium acetate (CH₃COONa).
- Siv: Feem ntau siv rau hauv biochemistry kom cov pH ruaj khov ntawm kwv yees li 4-6.
2. Lub hauv paus tsis siv neeg:
- Cov Cheebtsam: Lub hauv paus tsis muaj zog thiab nws cov kua qaub conjugate.
– Piv txwv li: Cov kua ammonia uas muaj ammonia (NH₃) thiab ammonium chloride (NH₄Cl).
- Kev Siv: Siv rau hauv cov ntawv thov uas xav tau pH ruaj khov ntawm ib puag ncig 9-11.
Cov Ntawv Thov Kev daws teeb meem tsis muaj zog
Cov kev daws teeb meem buffer muaj ntau yam kev siv, txij li cov chaw kuaj tshuaj mus rau kev lag luam zaub mov, kev kho mob, thiab ib puag ncig. Nov yog qee qhov kev siv tseem ceeb:
1. Cov ntawv thov hauv Kev Tshawb Fawb Txog Kev Noj Qab Haus Huv
– Ntshav: Ntshav yog ib qho piv txwv ntawm cov tshuaj buffer ntuj tseem ceeb heev. Lub kaw lus buffer tseem ceeb hauv cov ntshav yog lub kaw lus carbonic acid-bicarbonate, uas tswj cov pH ntawm cov ntshav tib neeg nyob ib puag ncig 7,4. Kev tsis sib npaug ntawm lub kaw lus buffer no tuaj yeem ua rau muaj mob hnyav xws li acidosis thiab alkalosis.
– Cov Tshuaj: Muaj ntau cov tshuaj uas khaws cia rau hauv cov tshuaj buffer kom lawv ruaj khov thiab ua haujlwm tau zoo. Piv txwv li, cov tshuaj buffer siv rau hauv cov tshuaj tiv thaiv kab mob kom lawv ruaj khov.
2. Cov ntawv thov hauv Kev Lag Luam
– Kev Lag Luam Khoom Noj: Hauv kev lag luam khoom noj, cov tshuaj buffer yog siv los tswj pH ntawm cov khoom noj thaum lub sijhawm tsim khoom thiab khaws cia. Piv txwv li, cov buffers raug ntxiv rau cov khoom noj mis nyuj kom tswj tau pH kom zoo thiab tiv thaiv kev puas tsuaj.
- Kev Tsim Ntawv: Thaum lub sijhawm ua ntawv, cov tshuaj buffer yog siv los tswj cov pH ntawm cov ntawv nplaum kom cov fibers tsis puas thaum lub sijhawm tsim khoom.
3. Cov Ntawv Thov Hauv Kev Tshawb Fawb
– Biochemistry: Cov tshuaj buffer yog qhov tseem ceeb hauv kev tshawb fawb biochemical. Lawv siv rau hauv ntau yam kev sim enzymatic kom tswj tau qhov pH zoo tshaj plaws uas cov enzymes xav tau rau kev ua haujlwm siab tshaj plaws.
– Gel Electrophoresis: Hauv txoj kev gel electrophoresis, uas yog siv rau kev sib cais ntawm DNA, RNA, thiab cov protein, cov tshuaj buffer yog siv los ua kom pH tsis hloov pauv thoob plaws hauv cov txheej txheem.
4. Cov ntawv thov hauv kev tiv thaiv ib puag ncig
– Kev Kho Dej Pov Tseg: Hauv kev kho dej pov tseg, cov tshuaj buffer yog siv los kho qhov pH ntawm cov dej kom cov txheej txheem sib cais cov pa phem ua haujlwm tau zoo dua thiab tiv thaiv kev puas tsuaj rau lub kaw lus kho.
– Kev Tswj Xyuas Huab Cua Phem: Cov tshuaj buffer siv rau hauv cov qhov cub hluav taws xob hauv kev lag luam kom tshem tawm cov pa roj acid phem ua ntej lawv raug tso tawm mus rau hauv huab cua.
Xaus
Cov tshuaj buffer ua lub luag haujlwm tseem ceeb hauv ntau yam ntawm lub neej, ob qho tib si hauv kev tshawb fawb thiab hauv kev siv txhua hnub. Los ntawm kev nkag siab txog cov ntsiab cai yooj yim, hom, thiab kev siv ntawm cov tshuaj buffer, peb tuaj yeem nkag siab zoo dua txog qhov tseem ceeb ntawm kev tswj hwm pH ruaj khov hauv ntau yam tshuaj lom neeg thiab kab mob.
Cov haujlwm sib txawv thiab cov txiaj ntsig ntawm cov tshuaj buffer solutions qhia txog qhov tseem ceeb ntawm kev paub no rau ntau yam kev kawm, txij li kev kho mob mus rau kev lag luam. Yog li ntawd, kev nkag siab txog cov tshuaj buffer solutions yog ib qho tseem ceeb uas tsis yog tsuas yog pab cov kws tshawb fawb thiab cov kws tshawb fawb xwb tab sis kuj pab cov zej zog dav dua hauv lub neej txhua hnub.
