Qhov sib txawv tseem ceeb ntawm qhov sib npaug ntawm qhov sib npaug thiab qhov kawg yog qhov sib npaug ntawm qhov sib npaug hauv qhov titration yog qhov taw tes ntawm qhov ntxiv titrant yog tshuaj sib npaug tag nrho rau cov tshuaj ntsuam xyuas hauv cov qauv thaum qhov kawg yog qhov taw qhia qhov ntsuas hloov nws. xim.
Titration yog cov txheej txheem peb siv dav hauv kev tshuaj ntsuam chemistry los txiav txim siab acids, bases, oxidants, reductants, hlau ions thiab ntau lwm hom. Nyob rau hauv ib tug titration, ib tug tshuaj tiv thaiv tshwm sim. Ntawm no, ib qho tshuaj ntsuam xyuas nrog tus qauv reagent, uas peb hu ua titrant. Qee lub sij hawm peb siv tus txheej txheem tseem ceeb, uas yog cov tshuaj purified thiab ruaj khov, raws li cov ntaub ntawv siv hauv txoj kev titrimetric. Peb siv qhov taw qhia txhawm rau txhawm rau txheeb xyuas qhov kawg ntawm cov tshuaj tiv thaiv. Tab sis, nws tsis yog lub ntsiab lus tiag tiag uas cov tshuaj tiv thaiv chemical xaus. Qhov tseeb point yog qhov sib npaug.
Endpoint yog dab tsi?
Nyob rau hauv txhua qhov kev sib tw, qhov kawg yog qhov taw qhia qhov taw qhia hloov nws cov xim. Los yog lwm yam peb tuaj yeem siv qhov kev hloov pauv hauv cov lus teb rau kev txheeb xyuas qhov kawg. Piv txwv li, HCl thiab NaOH teb 1: 1 thiab tsim NaCl thiab dej. Rau qhov titration no, peb tuaj yeem siv qhov taw qhia phenolphthalein, uas muaj xim liab nyob rau hauv nruab nrab nruab nrab thiab tig mus rau tsis muaj xim nyob rau hauv nruab nrab acidic. Yog tias peb muab HCl tso rau hauv lub khob titration thiab rau qhov ntawd, yog tias peb ntxiv ib qho phenolphthalein poob, nws yuav tsis muaj xim.
Daim duab 02: Qhov kawg yog qhov hloov pauv xim
Thaum lub sijhawm titration, peb tuaj yeem ntxiv NaOH los ntawm burette thiab maj mam, HCl thiab NaOH yuav hnov mob hauv lub khob. Yog tias peb coj tib qhov sib npaug ntawm ob txoj kev daws teeb meem, thaum peb ntxiv qhov sib npaug ntawm NaOH rau lub khob, cov tshuaj hauv lub khob yuav tig mus rau lub teeb liab dawb. Qhov no yog qhov chaw uas peb nres qhov titration (endpoint). Peb xav txog, ntawm qhov no, cov tshuaj tiv thaiv tiav.
Dab tsi yog Equivalence Point?
Qhov sib npaug ntawm qhov titration yog lub ntsiab lus ntawm qhov ntxiv titrant yog tshuaj sib npaug tag nrho rau cov tshuaj ntsuam xyuas hauv cov qauv. Qhov no yog lub ntsiab lus uas cov tshuaj tiv thaiv ua tiav stoichiometrically.
Daim duab 01: Cov ntsiab lus sib npaug rau cov kua qaub muaj zog thiab tsis muaj zog acid titration
Txawm hais tias peb txiav txim siab qhov kawg ntawm qhov taw qhia xim hloov, nws yog, feem ntau, tsis yog qhov kawg ntawm cov tshuaj tiv thaiv. cov tshuaj tiv thaiv ua tiav me ntsis ua ntej lub ntsiab lus ntawd. Ntawm qhov sib npaug ntawm qhov sib npaug, qhov nruab nrab yog nruab nrab. Hauv qhov piv txwv uas tau tham hauv nqe lus dhau los, tom qab ntxiv ib qho ntxiv NaOH poob, qhov nruab nrab yuav qhia cov xim yooj yim ntawm phenolphthalein, uas peb coj los ua qhov kawg.
Dab tsi yog qhov sib txawv ntawm Equivalence Point thiab Endpoint?
Qhov sib npaug ntawm qhov titration yog lub ntsiab lus ntawm qhov ntxiv titrant yog tshuaj sib npaug tag nrho rau cov tshuaj ntsuam xyuas hauv cov qauv thaum qhov kawg taw tes yog qhov taw qhia qhov ntsuas hloov nws cov xim. Qhov no yog qhov sib txawv tseem ceeb ntawm qhov sib npaug ntawm qhov sib npaug thiab qhov kawg. Ntxiv mus, qhov sib npaug taw tes ib txwm los ua ntej qhov kawg ntawm qhov titration.
Summary – Equivalence Point vs Endpoint
Hauv kev sib tw, peb muaj ob lub ntsiab lus tseem ceeb; uas yog, qhov sib npaug point thiab qhov kawg ntawm qhov titration. Qhov sib txawv tseem ceeb ntawm qhov sib npaug ntawm qhov sib npaug thiab qhov kawg yog qhov sib npaug ntawm qhov sib npaug hauv qhov kev sib tw yog qhov taw tes ntawm qhov ntxiv titrant yog tshuaj lom neeg sib npaug tag nrho rau cov tshuaj ntsuam xyuas hauv cov qauv thaum qhov kawg yog qhov taw qhia qhov ntsuas hloov nws cov xim.
