Kev tsim kho ntawm ph meter
Lub pH meter yog ib qho cuab yeej siv los ntsuas pH tus nqi ntawm cov tshuaj. Lub pH meter ua haujlwm ntawm lub hauv paus ntsiab lus ntawm lub roj teeb galvanic. Lub zog electromotive nruab nrab ntawm ob lub electrodes ntawm lub roj teeb galvanic yog raws li Nernst txoj cai, uas tsis yog tsuas yog muaj feem xyuam rau cov khoom ntawm electrode nws tus kheej, tab sis kuj muaj feem xyuam rau cov concentration ntawm hydrogen ions hauv cov tshuaj. Muaj kev sib raug zoo ntawm electromotive quab yuam ntawm thawj lub roj teeb thiab cov concentration ntawm hydrogen ions, thiab qhov tsis zoo logarithm ntawm cov concentration ntawm hydrogen ions yog pH tus nqi. Lub pH meter yog ib qho cuab yeej tshuaj ntsuam xyuas dav siv hauv kev ua liaj ua teb, kev tiv thaiv ib puag ncig thiab kev lag luam. Av pH yog ib qho tseem ceeb ntawm cov khoom tseem ceeb ntawm cov av. Cov yam ntxwv xws li qhov kub thiab txias thiab lub zog ionic ntawm cov tshuaj yuav tsum tau kuaj yuav tsum tau txiav txim siab hauv cov txheej txheem kev txiav txim siab pH.
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txoj cai
pH yog dab tsi? pH yog ib lo lus luv luv ntawm lo lus Latin "Pondus hydrogenii" (Pondus=siab, siab hydrogenium=}hydrogen), uas yog siv los ntsuas qhov kev ua ntawm hydrogen ions hauv ib yam khoom. Cov dej num no ncaj qha ntsig txog acidity, nruab nrab thiab alkalinity ntawm cov kua dej aqueous. Cov dej yog tshuaj nruab nrab, tab sis nws tsis yog tsis muaj ions. Txawm hais tias cov dej ntshiab huv yog me ntsis dissociated: Hais lus nruj me ntsis, hydrogen nuclei tsis muaj nyob hauv lub xeev dawb ua ntej hydration nrog dej molecules.
kev saib xyuas
1. Cia ntawm pH iav electrodes
Lub sij hawm luv luv: khaws cia hauv cov tshuaj tsis haum nrog pH=4;
Lub sij hawm ntev: Khaws hauv cov tshuaj tsis haum nrog pH=7.
2. Kev ntxuav ntawm pH iav electrode
Kev kis kab mob ntawm lub iav electrode qhov muag yuav ncua lub sij hawm teb electrode. Cov av tuaj yeem raug muab tshem tawm nrog CCl4 lossis tshuaj xab npum, thiab tom qab ntawd tsau hauv dej distilled rau ib hnub thiab hmo ntuj ua ntej siv txuas ntxiv. Thaum cov pa phem hnyav, nws tuaj yeem muab tso rau hauv 5 feem pua HF cov tshuaj rau 10-20 feeb, yaug nrog dej tam sim ntawd, thiab muab tso rau hauv 0.1N HCl tov rau ib hnub thiab hmo ntuj ua ntej siv txuas ntxiv. .
3. Kev kho cov iav electrode aging
Kev laus ntawm cov iav electrode yog cuam tshuam nrog kev hloov pauv ntawm cov kua nplaum txheej txheej. Cov laus electrodes muaj cov lus teb qeeb, siab membrane tsis kam, thiab nqes qis. Etching tawm txheej txheej nplaum nrog hydrofluoric acid feem ntau txhim kho electrode kev ua tau zoo. Yog tias txoj kev no tuaj yeem siv tsis tu ncua tshem tawm cov nplaum nplaum sab hauv thiab sab nrauv, lub neej ntawm electrode yuav luag tsis txwv.
4. Cia khoom siv electrode
Qhov zoo tshaj plaws cia tshuaj rau cov nyiaj-nyiaj chloride electrode yog saturated potassium chloride tov. High-concentration potassium chloride tov tuaj yeem tiv thaiv cov nyiaj chloride los ntawm precipitating ntawm cov kua hlws ris thiab ua kom cov dej sib txuas ua haujlwm. Txoj kev no kuj tseem siv tau rau kev khaws cia ntawm cov khoom siv electrodes.
