pH vs Acidity
Acidity thiab pH yog ob nqe lus zoo sib xws hauv chemistry. pH yog ib lo lus uas feem ntau siv hauv chav kuaj. Nws cuam tshuam nrog kev ntsuas acidity thiab ntsuas qhov pib.
Acidity
Acids tau txhais ntau txoj hauv kev los ntawm ntau tus kws tshawb fawb. Arrhenius txhais cov kua qaub ua ib yam khoom uas pub H3O+ ions hauv cov tshuaj. Bronsted- Lowry txhais lub hauv paus ua ib yam khoom uas tuaj yeem txais tau ib qho proton. Lewis acid txhais tau ntau dua li ob qho saum toj no. Raws li nws, txhua tus khub electron pub dawb yog lub hauv paus. Raws li lub Arrhenius los yog Bronsted-Lowry txhais, ib tug compound yuav tsum muaj ib tug hydrogen thiab muaj peev xwm los pub nws raws li ib tug proton los ua ib tug acid. Tab sis raws li Lewis, tuaj yeem muaj cov molecules, uas tsis muaj hydrogen, tab sis tuaj yeem ua raws li cov kua qaub. Piv txwv li, BCl3 yog Lewis acid, vim nws tuaj yeem txais ib khub electron. Ib qho cawv tuaj yeem yog Bronsted-Lowry acid, vim tias nws tuaj yeem pub dawb rau proton; txawm li cas los xij, raws li Lewis, nws yuav yog lub hauv paus. Txawm hais tias cov ntsiab lus saum toj no, peb ib txwm txheeb xyuas cov kua qaub ua tus pub dawb proton. Acids muaj qaub saj. Txiv qaub kua txiv, vinegar yog ob tug acids peb tuaj nyob rau hauv peb lub tsev. Lawv hnov mob nrog cov hauv paus ua dej, thiab nrog cov hlau los ua H2; yog li, nce hlau corrosion tus nqi. Acidity yog lub xeev ntawm kev ua kua qaub. Qhov no muaj feem xyuam rau qib ntawm kev ua kua qaub (muaj zog lossis tsis muaj zog acid).
pH
pH yog qhov ntsuas uas siv tau los ntsuas cov kua qaub lossis qhov pib hauv cov tshuaj. Qhov ntsuas muaj tus lej ntawm 1 txog 14. pH 7 yog suav tias yog tus nqi nruab nrab. Cov dej ntshiab yog hais tias muaj pH 7. Nyob rau hauv pH nplai, los ntawm 1-6 acids yog sawv cev. Cov kua qaub tuaj yeem muab faib ua ob, raws li lawv lub peev xwm los sib cais thiab tsim cov protons. Cov kua qaub muaj zog zoo li HCl, HNO 3 yog ionized tag nrho hauv cov tshuaj kom muab cov protons. Cov acids tsis muaj zog xws li CH3COOH yog ib feem ntawm kev sib cais thiab muab cov protons tsawg dua. Cov kua qaub nrog pH 1 tau hais tias muaj zog heev, thiab raws li tus nqi pH nce, acidity txo. Yog li cov pH qhov tseem ceeb tshaj 7 qhia txog qhov tseem ceeb. Raws li qhov pib nce, pH tus nqi kuj yuav nce ntxiv thiab cov hauv paus muaj zog yuav muaj pH tus nqi 14.
pH nplai yog logarithmic. Nws tuaj yeem sau tau raws li hauv qab no hauv cov txheeb ze rau H + concentration hauv cov tshuaj.
pH=-log [H+
Nyob hauv qhov kev daws teeb meem, tsis muaj H+s. Yog li ntawd, nyob rau hauv ib qho xwm txheej zoo li ntawd, los ntawm -log [OH–] tus nqi pOH tuaj yeem txiav txim siab.
Vim, pH + pOH=14
Yog li ntawd, tus nqi pH ntawm cov tshuaj yooj yim kuj tuaj yeem suav. Muaj pH ntsuas thiab pH cov ntaub ntawv nyob rau hauv lub chaw soj nstuam, uas yog siv los ntsuas pH tus nqi ncaj qha. pH cov ntaub ntawv yuav muab kwv yees pH qhov tseem ceeb, whereas pH meters muab qhov tseeb tshaj pH ntawv.
Qhov txawv ntawm Acidity thiab pH yog dab tsi?
• pH ntsuas tag nrho [H+] hauv kev daws thiab nws yog qhov ntsuas ntau ntawm acidity. Acidity muab qhov qhia tau zoo ntawm qib ntawm cov kua qaub tam sim no hauv cov tshuaj.
• Raws li tus nqi pH nce, acidity txo qis, thiab rov ua dua.
• pH kuj ntsuas qhov pib, tsis yog acidity xwb.
