pH ntawm Cov Acids thiab Bases: Chemistry Basics Koj Yuav Tsum Paub
Pendahuluuan
pH yog ib chav ntsuas qhov acidity lossis alkalinity ntawm cov tshuaj. Lub tswv yim ntawm pH yog ib qho tseem ceeb hauv chemistry, tshwj xeeb tshaj yog qhov tseem ceeb hauv ntau yam txheej txheem kev lag luam, chaw soj nstuam, thiab lub neej txhua hnub. Tsab xov xwm no yuav tshawb nrhiav pH ntawm cov kua qaub thiab cov hauv paus, suav nrog lawv cov lus txhais, kev txiav txim siab, thiab kev siv hauv lub neej txhua hnub.
Nkag Siab Txog pH
Lub ntsuas pH yog los ntawm Latin "potentia hydrogenii," txhais tau tias 'lub zog ntawm hydrogen.' pH yog qhov ntsuas ntawm kev ua haujlwm ntawm hydrogen ions (H+) hauv cov kua. Lub pH nplai yog txij li 0 txog 14, qhov twg:
- pH 7 suav tias yog nruab nrab, zoo li dej ntshiab.
- pH tsawg dua 7 qhia txog cov khoom acidic.
- pH ntau dua 7 qhia txog cov khoom alkaline.
pH nplai
Yuav kom nkag siab txog qhov ntsuas pH, nws yog ib qho tseem ceeb kom paub tias nws yog qhov ntsuas logarithmic. Txhua qhov kev hloov pauv ntawm ib chav pH sawv cev rau kev hloov pauv kaum npaug ntawm H + ion kev ua haujlwm. Piv txwv li, cov tshuaj uas muaj pH ntawm 3 yog kaum npaug ntau dua li cov tshuaj uas muaj pH ntawm 4.
Kev Txhais ntawm Acids thiab Bases
Cov kua qaub yog ib yam khoom uas tso tawm cov hydrogen ions (H+) thaum yaj rau hauv dej. Piv txwv ntawm cov kua qaub uas feem ntau pom muaj nyob rau hauv lub neej txhua hnub suav nrog hydrochloric acid (HCl) hauv plab thiab citric acid hauv txiv kab ntxwv.
Ib lub hauv paus, lossis alkali, yog ib yam khoom uas tuaj yeem txais cov hydrogen ions lossis tso cov hydroxide ions (OH-) thaum yaj hauv dej. Sodium hydroxide (NaOH) thiab potassium hydroxide (KOH) yog cov piv txwv ntawm cov hauv paus muaj zog uas feem ntau siv hauv kev lag luam.
Kev txiav txim siab pH
Lub pH ntawm cov tshuaj ntsuas tau siv ntau txoj kev:
1. Cov Cim Qhia Txog Acid-Base: Daim ntawv Litmus thiab cov tshuaj qhia xws li phenolphthalein lossis bromothymol xiav tuaj yeem muab kev kwv yees txog pH. Cov cim qhia hloov xim nyob ntawm pH ntawm cov tshuaj uas tab tom sim.
2. Lub Ntsuas pH: Yog xav ntsuas kom raug dua, siv lub ntsuas pH digital. Lub cuab yeej no ntsuas lub zog hluav taws xob ntawm ob lub electrodes, uas tom qab ntawd hloov mus ua tus nqi pH.
3. Kev Titration Acid-Base: Txoj kev no yog siv los txiav txim siab qhov concentration ntawm cov kua qaub lossis cov base hauv cov kua. Titration suav nrog kev ntxiv cov kua uas paub qhov concentration thiab ntim kom txog thaum qhov kev sib xyaw ntawm ob qho kua tiav.
Cov kua qaub nyob rau hauv lub neej txhua hnub
Cov kua qaub muaj ntau lub luag haujlwm tseem ceeb hauv peb lub neej:
1. Cov kua qaub hauv cov khoom noj: Muaj ntau yam khoom noj muaj cov kua qaub ntuj, xws li kua txiv hmab (acetic acid) thiab txiv hmab txiv ntoo xws li txiv qaub thiab txiv kab ntxwv (citric acid). Cov kua qaub kuj tseem siv ua cov tshuaj tiv thaiv khoom noj.
2. Cov kua qaub hauv kev lag luam: Sulfuric acid (H2SO4) yog ib qho ntawm cov khoom siv tshuaj lom neeg tseem ceeb tshaj plaws uas siv rau hauv kev tsim cov chiv, cov tshuaj lom neeg hauv kev lag luam, thiab kev ua cov hlau.
3. Kev Ua Haujlwm ntawm Cov Acid: Cov kua qaub hauv plab, uas muaj cov kua qaub hydrochloric, yog qhov tseem ceeb rau kev zom cov khoom noj hauv plab. Cov amino acids yog cov khoom siv tsim cov protein tseem ceeb rau lub neej.
Cov hauv paus hauv Lub Neej Txhua Hnub
Cov lus kuj muaj ntau yam kev siv:
1. Cov Alkalines Hauv Tsev Neeg: Cov khoom siv ntxuav hauv tsev xws li cov tshuaj dawb thiab cov tshuaj ntxuav feem ntau yog alkaline vim tias lawv ua tau zoo rau kev rhuav tshem cov av thiab roj.
2. Cov hauv paus hauv kev lag luam: Cov hauv paus yog siv rau hauv kev tsim xab npum thiab ntawv, nrog rau hauv kev ua dej thiab textile. Sodium carbonate (soda ash) yog ib qho hauv paus uas siv rau hauv kev ua iav.
3. Kev Noj Qab Haus Huv: Cov tshuaj Antacids yog ib qho piv txwv ntawm cov tshuaj siv los tshem tawm cov kua qaub ntau dhau hauv plab thiab txo cov tsos mob kub siab.
Cov Kev Tshwm Sim Acid-Base
Qhov kev sib xyaw ntawm cov kua qaub thiab cov hauv paus hu ua neutralization. Hauv qhov kev sib xyaw no, cov kua qaub thiab cov hauv paus sib xyaw ua ke los ua dej thiab ntsev. Cov qauv dav dav rau qhov kev sib xyaw no yog:
\[ \text{Acid} + \text{Base} \rightarrow \text{Ntxhiab} + \text{Dej} \]
Ib qho piv txwv yooj yim ntawm kev ua kom tsis muaj zog yog qhov ntxiv ntawm HCl nrog NaOH:
\[ \text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O} \]
Qhov kev tshuaj tiv thaiv no qhia tau tias cov tshuaj uas muaj cov khoom muaj zog acidic thiab cov khoom yooj yim tuaj yeem hloov pauv mus ua cov tshuaj uas muaj cov khoom tsis muaj zog.
tsis
Ib qho buffer yog ib qho kua uas tswj tau pH kom ruaj khov txawm tias thaum ntxiv cov kua qaub lossis cov hauv paus. Cov buffers yog qhov tseem ceeb rau ntau yam txheej txheem biochemical hauv cov tsiaj txhu uas muaj sia nyob. Piv txwv li, cov buffers hauv cov ntshav tswj cov pH ntshav kom nyob rau hauv ib qho nqaim, uas yog qhov tseem ceeb rau kev ua haujlwm ntawm lub cev ib txwm muaj.
Cov khoom tseem ceeb ntawm lub buffer yog cov kua qaub tsis muaj zog thiab nws cov conjugate base lossis cov kua qaub tsis muaj zog thiab nws cov conjugate acid. Piv txwv li, cov acetic acid thiab sodium acetate sib xyaw ua ib lub buffer uas tswj tau pH ntawm kwv yees li 4.75.
Kev Siv Cov Kev Tshawb Fawb Txog pH Hauv Ntau Qhov Chaw
1. Kev Ua Liaj Ua Teb: pH ntawm av cuam tshuam rau qhov muaj cov as-ham rau cov nroj tsuag. Cov neeg ua liaj ua teb feem ntau ntsuas pH ntawm av kom paub seb yuav siv chiv hom twg. Cov av uas muaj kua qaub ntau dhau los yog alkaline ntau dhau tuaj yeem kho tau los ntawm kev ntxiv txiv qaub ntsuab (kom nce pH) los yog sulfur (kom txo pH).
2. Ib puag ncig: Qhov pH ntawm cov dej hauv cov dej ntws thiab cov pas dej yog qhov qhia txog kev noj qab haus huv ntawm cov ecosystem hauv dej. Cov dej uas muaj kua qaub ntau dhau vim yog nag kua qaub tuaj yeem ua rau cov nroj tsuag thiab tsiaj txhu hauv dej puas tsuaj.
3. Tshuaj: Hauv kev tsim tshuaj, pH tuaj yeem cuam tshuam rau qhov ruaj khov ntawm cov khoom xyaw nquag. Kev lag luam tshuaj yuav tsum xyuas kom meej tias pH tsim nyog rau lawv cov khoom kom tswj tau qhov ua tau zoo thiab kev nyab xeeb ntawm tshuaj.
4. Tshuaj pleev ib ce: Cov khoom siv saib xyuas tawv nqaij thiab plaub hau muaj pH uas tau kho kom txo qhov khaus thiab tswj kom tawv nqaij thiab plaub hau noj qab nyob zoo.
Xaus
Tus pH ntawm cov kua qaub thiab cov hauv paus yog lub tswv yim tseem ceeb hauv chemistry uas muaj feem cuam tshuam dav rau ntau yam ntawm lub neej txhua hnub thiab kev lag luam. Kev nkag siab zoo txog pH thiab yuav ntsuas nws li cas yog qhov tseem ceeb rau kev siv cov kev paub no hauv kev tsim khoom, kev tswj hwm ib puag ncig, kev ua liaj ua teb, kev noj qab haus huv, thiab ntau ntxiv. Los ntawm kev nkag siab zoo dua txog cov kua qaub thiab cov hauv paus, peb tuaj yeem siv cov kev paub no los txhim kho peb lub neej zoo thiab kev noj qab haus huv ntawm peb ib puag ncig.
