Qhov sib txawv tseem ceeb ntawm pH thiab tsis yog qhov pH yog qhov ntsuas logarithmic whereas qhov tsis yog cov tshuaj aqueous.
Peb tuaj yeem siv pH ntawm cov kua los txiav txim seb nws puas yog cov kua qaub lossis lub hauv paus. Nws kuj tseem pab tau rau kev txiav txim siab lub peev xwm buffering ntawm ib qho tsis. Ib qho kev daws teeb meem tsis muaj qhov sib xyaw ntawm cov kua qaub tsis muaj zog thiab nws lub hauv paus conjugate, los yog rov qab. Yog li ntawd, nws zoo li tiv thaiv kev hloov pauv hauv pH ntawm cov tshuaj.
pH yog dab tsi?
pH yog qhov ntsuas logarithmic uas peb siv los txiav txim siab cov kua qaub lossis qhov pib ntawm cov kua dej aqueous. Nws yog lub hauv paus tsis zoo 10 logarithm ntawm hydrogen ion concentration ntsuas hauv chav tsev mol / L. Yog tias peb nthuav qhia nws meej dua, peb yuav tsum siv cov haujlwm ntawm hydrogen ions es tsis txhob siv cov concentration. Cov pH nplai muaj cov lej ntawm 0 txog 14. Cov kev daws teeb meem uas muaj pH tsawg dua 7 yog acidic thiab yog tias pH siab tshaj 7, nws yog ib qho kev daws teeb meem. Lub pH 7 qhia txog kev daws teeb meem nruab nrab, piv txwv li dej ntshiab.
Daim duab 01: pH ntawm Cov Cheebtsam sib txawv
Kev sib npaug rau kev txiav txim siab ntawm pH yog raws li hauv qab no:
pH=log10(aH+)
Ntawm no "a" yog kev ua haujlwm ntawm hydrogen ions (H+). pH tus nqi nyob ntawm qhov kub ntawm cov tshuaj raws li qhov kub thiab txias tuaj yeem hloov qhov kev ua ntawm ib hom tshuaj. Yog li ntawd, thaum muab pH ntawm cov kua dej aqueous, peb yuav tsum qhia qhov kub ntawm qhov pH ntsuas qhov tseeb. Peb siv pH nplai txhawm rau txiav txim siab qhov zoo ntawm cov dej, av, thiab lwm yam.
Dab tsi yog dab tsi?
A tsis yog ib qho tshuaj aqueous uas zoo li tiv thaiv kev hloov pauv hauv pH. Cov tshuaj no muaj ib tug sib tov ntawm ib tug qaug zog acid thiab nws conjugate puag los yog vice versa. Cov pH ntawm cov kev daws teeb meem no hloov me ntsis raws li qhov sib ntxiv ntawm cov kua qaub lossis lub hauv paus muaj zog.
Cov kua qaub tsis muaj zog (lossis lub hauv paus) thiab nws lub hauv paus conjugate (los yog conjugate acid) nyob rau hauv qhov sib npaug. Tom qab ntawd yog tias peb ntxiv qee cov kua qaub rau lub cev no, qhov sib npaug hloov mus rau cov kua qaub, thiab nws tsim cov kua qaub ntau dua siv cov hydrogen ions tso tawm los ntawm cov kua qaub ntxiv. Yog li ntawd, txawm hais tias peb cia siab tias yuav nce ntawm hydrogen ions thaum ntxiv cov kua qaub uas muaj zog, nws tsis nce ntau npaum li ntawd. Ib yam li ntawd, yog tias peb ntxiv lub hauv paus muaj zog, cov hydrogen ion concentration txo qis dua li qhov xav tau rau qhov ntau ntawm alkali ntxiv. Peb tuaj yeem ntsuas qhov kev tiv thaiv pH hloov raws li lub peev xwm tsis muaj peev xwm. Lub peev xwm tsis ntsuas qhov tsis kam ntawm qhov tsis kam rau pH hloov ntawm qhov sib ntxiv ntawm OH– ions (lub hauv paus). Peb tuaj yeem muab nws hauv qhov sib npaug raws li hauv qab no:
β=dn/d(pH)
qhov twg β yog qhov tsis muaj peev xwm, dn yog qhov tsis txaus ntseeg ntawm cov hauv paus ntxiv, thiab d (pH) yog qhov ua rau tsis muaj kev hloov pauv hauv pH.
Thaum xav txog cov ntawv thov ntawm cov buffers, cov kev daws teeb meem no yog tsim nyog los khaws cov pH kom raug rau kev ua kom muaj zog hauv cov kab mob. Ntxiv mus, cov no yog siv hauv kev lag luam hauv cov txheej txheem fermentation, teeb tsa cov xwm txheej raug rau dyes, hauv kev tshuaj xyuas tshuaj, ntsuas pH ntsuas, thiab lwm yam.
Qhov txawv ntawm pH thiab tsis yog dab tsi?
pH yog qhov ntsuas logarithmic uas peb siv los txiav txim siab cov kua qaub lossis qhov pib ntawm cov tshuaj aqueous whereas, qhov tsis yog cov tshuaj aqueous uas nyiam tiv thaiv kev hloov pauv hauv pH. Qhov no yog qhov sib txawv tseem ceeb ntawm pH thiab tsis. Tsis tas li ntawd, pH yog qhov ntsuas tseem ceeb hauv chemistry. Peb tuaj yeem ntsuas pH ntawm cov tshuaj siv pH meter lossis los ntawm kev sim. Tsis tas li ntawd, peb siv pH nplai txhawm rau txiav txim siab qhov zoo ntawm dej, av, thiab lwm yam. Ntawm qhov tod tes, kev siv cov kev daws teeb meem tsis yog los tswj qhov tseeb pH rau kev ua haujlwm enzymatic, hauv cov txheej txheem fermentation hauv kev lag luam, teeb tsa cov xwm txheej raug rau dyes, hauv tshuaj ntsuam xyuas, ntsuas pH ntsuas, thiab lwm yam. Peb ntsuas qhov tsis muaj peev xwm ntawm ib qho tsis siv tshuaj ntsuam xyuas.
Summary – pH vs Buffer
pH yog qhov ntsuas tseem ceeb uas peb siv hauv chemistry los ntsuas cov acidity r hauv paus ntawm kev daws. Buffers yog cov tshuaj daws teeb meem uas tuaj yeem tiv taus cov kev hloov pauv hauv pH. Yog li, qhov sib txawv ntawm pH thiab tsis yog qhov pH yog qhov ntsuas logarithmic whereas qhov tsis yog cov tshuaj aqueous.
