nag xob nag cua yog kev tsim cov khoom los ntawm kev daws teeb meem. Thaum pib, cov tshuaj tiv thaiv tshwm sim nyob rau hauv lub xeev ua kua, tom qab uas ib yam khoom yog tsim, uas yog hu ua "precipitate". Cov tshuaj tiv thaiv uas ua rau nws tsim muaj xws li kev tshawb fawb xws li "precipitator". Yog tias tsis muaj lub ntiajteb txawj nqus txaus (tso tawm) los nqa cov khoom nyuaj ua ke, cov sediment tseem nyob hauv kev ncua.
Tom qab kev daws teeb meem, tshwj xeeb tshaj yog thaum siv lub centrifuge compact, qhov teeb meem tuaj yeem hu ua "granule". Nws tuaj yeem siv los ua qhov nruab nrab. Cov kua uas nyob saum cov khoom uas tsis muaj nag lossis daus yog hu ua "supernatant". Cov dej nag yog cov hmoov tau los ntawm cov pob zeb seem. Lawv kuj muaj keeb kwm hu ua "paj". Thaum cov khoom tshwm nyob rau hauv daim ntawv ntawm tshuaj kho cellulose fibers, cov txheej txheem no feem ntau hu ua regeneration.
Element solubility
Qee lub sij hawm qhov tsim ntawm precipitate qhia qhov tshwm sim ntawm cov tshuaj tiv thaiv. Yog ibnag lossis daus los ntawm kev daws ntawm cov nyiaj nitrate yog nchuav rau hauv cov kua ntawm sodium chloride, tom qab ntawd kev xav txog tshuaj lom neeg tshwm sim nrog kev tsim cov xim dawb los ntawm cov hlau zoo nkauj. Thaum cov kua poov tshuaj iodide reacts nrog lead (II) nitrate, ib tug daj precipitate ntawm lead (II) iodide yog tsim.
Precipitation tuaj yeem tshwm sim yog tias cov ntsiab lus ntawm cov khoom sib xyaw ua ke ntau tshaj nws cov solubility (piv txwv li, thaum sib xyaw cov khoom sib txawv lossis hloov lawv qhov kub). Ua tiav nag lossis daus tsuas tuaj yeem tshwm sim sai ntawm cov tshuaj supersaturated.
Nyob rau hauv cov khib nyiab, txheej txheem tshwm sim thaum qhov concentration ntawm ib yam khoom yog siab tshaj qhov solubility txwv nyob rau hauv lwm tus tswv lub cev. Piv txwv li, vim yog qhov txias txias los yog ion implantation, qhov kub thiab txias yog siab txaus uas diffusion tuaj yeem ua rau kev sib cais ntawm cov khoom thiab tsim cov precipitate. Tag nrho cov solid-state deposition feem ntau yog siv rau cov synthesis ntawm nanoclusters.
dej ntau dhau
Ib kauj ruam tseem ceeb hauv cov txheej txheem nag lossis daus yog qhov pib ntawm nucleation. Lub creation ntawm ib tug hypothetical khoom particle yog tsim los ntawm ib tug interface, uas tau kawg yuav tsum tau ib co zog raws li tus txheeb ze nto motion ntawm cov khoom thiab cov kev daws teeb meem. Yog tsis muaj cov qauv nucleation tsim nyog, supersaturation tshwm sim.
Ib qho piv txwv ntawm nag lossis daus: tooj liab los ntawm cov hlau uas tau hloov los ntawm cov nyiaj mus rau hauv cov tshuaj ntawm cov hlau nitrate, uas nws dipped. Ntawm chav kawm, tom qab cov kev sim no, cov khoom siv precipitates. Cov tshuaj tiv thaiv nag lossis daus tuaj yeem siv los tsim cov xim. Thiab kuj tshem tawmntsev los ntawm dej thaum nws ua thiab nyob rau hauv classical qualitative inorganic tsom xam. Qhov no yog li cas tooj liab tso.
Porphyrin crystals
Ntxhais nag los kuj tseem muaj txiaj ntsig thaum lub sijhawm kev sib cais ntawm cov khoom siv tshuaj tiv thaiv thaum ua tiav. Qhov zoo tshaj plaws, cov tshuaj no yog insoluble hauv cov tshuaj tiv thaiv.
Yog li cov khoom precipitates tawm raws li nws cov ntaub ntawv, nyiam dua tsim cov muaju ntshiab. Ib qho piv txwv ntawm qhov no yog cov synthesis ntawm porphyrins hauv boiling propionic acid. Thaum cov tshuaj tiv thaiv sib tov yog txias rau chav tsev kub, cov muaju ntawm cov khoom no poob rau hauv qab ntawm lub nkoj.
Ntxhais dej nag kuj tuaj yeem tshwm sim thaum ntxiv cov kuab tshuaj tiv thaiv, uas ua rau txo cov dej tsis txaus ntawm cov khoom xav tau. Cov khoom tuaj yeem sib cais yooj yim los ntawm kev pom, decantation lossis centrifugation. Ib qho piv txwv yog cov synthesis ntawm chromium chloride tetraphenylporphyrin: dej ntxiv rau cov tshuaj tiv thaiv DMF thiab cov khoom precipitates. Cov dej nag kuj tseem muaj txiaj ntsig zoo hauv kev ua kom huv ntawm tag nrho cov khoom xyaw: cov crude bdim-cl yog decomposed kiag li nyob rau hauv acetonitrile thiab muab pov tseg rau hauv ethyl acetate, qhov twg nws precipitates. Lwm qhov tseem ceeb ntawm kev tiv thaiv cov kuab tshuaj yog ethanol nag lossis daus los ntawm DNA.
Hauv metallurgy, cov kua dej nag kuj yog ib txoj hauv kev zoo los ua kom cov alloys. Cov txheej txheem kev lwj no yog hu ua hardening ntawm cov khoom tivthaiv.
Sawv cev siv tshuaj sib npaug
Precipitation tshuaj tiv thaiv piv txwv: aqueous silver nitrate (AgNO 3)ntxiv rau cov tshuaj uas muaj poov tshuaj chloride (KCl), decomposition ntawm cov khoom dawb yog pom, tab sis twb nyiaj (AgCl).
Nws, dhau los, tsim cov khoom siv hlau, uas pom tau tias yog nag lossis daus.
Cov tshuaj tiv thaiv nag lossis daus no tuaj yeem sau nrog rau qhov tseem ceeb ntawm cov molecules dissociated hauv cov tshuaj sib xyaw ua ke. Qhov no hu ua ionic equation.
Txoj kev kawg los tsim cov tshuaj tiv thaiv no yog hu ua kev sib cog lus dawb huv.
nag xob nag cua sib txawv
Ntsuab thiab liab-xim av me ntsis ntawm cov qauv limestone sib haum rau cov khib nyiab ntawm Fe 2+ thiab Fe 3+ oxides thiab hydroxides.
Ntau lub tebchaw uas muaj cov hlau ions tsim cov dej nag nrog cov xim sib txawv. Hauv qab no yog cov duab ntxoov ntxoo rau ntau yam hlau depositions. Txawm li cas los xij, ntau qhov sib xyaw no tuaj yeem tsim cov xim sib txawv ntawm cov npe teev.
Lwm cov koom haum feem ntau tsim cov dej nag dawb.
Anion thiab cation analysis
nag xob nag cua yog qhov tseem ceeb hauv kev kuaj xyuas hom cation hauv ntsev. Ua li no, cov alkali ua ntej reacts nrog ib qho tsis paub tivthaiv los ua ib qho khoom. Qhov no yog nag lossis daus ntawm hydroxide ntawm ib qho ntsev. Txhawm rau txheeb xyuas cov cation, nco ntsoov cov xim ntawm cov precipitate thiab nws cov solubility ntau dhau. Cov txheej txheem zoo sib xws feem ntau yog siv nyob rau hauv ib ntus - piv txwv li, kev sib xyaw ntawm barium nitrate yuav hnov mob nrog sulfate ions los ua cov khoom precipitate ntawm barium sulfate, qhia qhov tshwm sim uas cov khoom thib ob muaj ntau..
txheej txheem digestion
Kev laus ntawm cov nag lossis daus tshwm sim thaum cov khoom tsim tshiab tseem nyob hauv cov tshuaj uas nws los nag, feem ntau ntawm qhov kub siab dua. Qhov no ua rau kom huv thiab coarser particle deposits. Cov txheej txheem physicochemical hauv qab plab yog hu ua Ostwald maturation. Nov yog ib qho piv txwv ntawm nag lossis daus protein.
Cov tshuaj tiv thaiv no tshwm sim thaum cations thiab anions hauv cov tshuaj hydrophyte ua ke los tsim cov khoom tsis sib xws, heteropolar hu ua precipitate. Txawm hais tias qhov kev tshwm sim no tshwm sim tuaj yeem paub tseeb los ntawm kev siv cov ntsiab lus ntawm cov dej rau cov khoom siv molecular. Txij li thaum tsis yog tag nrho cov tshuaj tiv thaiv aqueous tsim precipitates, nws yog ib qho tsim nyog yuav tsum paub koj tus kheej nrog cov kev cai solubility ua ntej txiav txim siab lub xeev ntawm cov khoom thiab sau tag nrho cov ionic equation. Muaj peev xwm kwv yees cov kev cuam tshuam no tso cai rau cov kws tshawb fawb los txiav txim siab seb cov ions muaj nyob rau hauv kev daws teeb meem. Nws kuj tseem pab cov nroj tsuag muaj tshuaj los ntawm kev rho tawm cov khoom los ntawm cov tshuaj tiv thaiv no.
Txhua yam nag lossis daus
Lawv yog cov tshuaj tiv thaiv ionic insoluble uas tsim thaum qee cov cations thiab anions ua ke hauv cov tshuaj aqueous. Cov kev txiav txim ntawm sludge tsim tuaj yeem sib txawv. Qee qhov kev tawm tsam yog qhov kub thiab txias, xws li cov kev daws teeb meem siv rau buffers, thaum lwm tus tsuas yog cuam tshuam nrog cov concentration ntawm cov tshuaj. Cov khoom tsim nyob rau hauv nag lossis daus cov tshuaj tiv thaiv yog crystalline Cheebtsam thiabtej zaum yuav raug tshem tawm nyob rau hauv tag nrho cov kua los yog poob mus rau hauv qab ntawm cov tshuaj. Cov dej seem yog hu ua supernatant. Ob lub ntsiab lus sib xws (precipitate thiab supernatant) tuaj yeem sib cais los ntawm ntau txoj kev, xws li pom, ultracentrifugation lossis decantation.
Kev sib tshuam ntawm nag lossis daus thiab hloov pauv
Kev siv cov kev cai ntawm solubility yuav tsum to taub yuav ua li cas ions react. Feem ntau ntawm cov nag lossis daus sib cuam tshuam yog ib qho los yog ob txoj kev hloov chaw. Thawj qhov kev xaiv tshwm sim thaum ob lub ionic reactants dissociate thiab khi rau cov anion los yog cation ntawm lwm yam khoom. Molecules hloov ib leeg raws li lawv cov nqi raws li cation lossis anion. Qhov no tuaj yeem pom yog "hloov cov neeg koom tes". Ntawd yog, txhua tus ntawm ob lub reagents "loses" nws tus khub thiab tsim kev sib raug zoo nrog rau lwm tus, piv txwv li, tshuaj los nag nrog hydrogen sulfide tshwm sim.
Qhov kev hloov pauv ob zaug yog tshwj xeeb cais raws li cov txheej txheem solidification thaum cov tshuaj sib npaug hauv nqe lus nug tshwm sim hauv cov tshuaj aqueous thiab ib qho ntawm cov khoom tsim tawm yog insoluble. Ib qho piv txwv ntawm cov txheej txheem no yog qhia hauv qab no.
Ob lub reagents yog aqueous thiab ib yam khoom yog khoom. Txij li thaum tag nrho cov khoom yog ionic thiab kua, lawv dissociate thiab yog li ntawd muaj peev xwm yaj tag rau ib leeg. Txawm li cas los xij, muaj rau lub hauv paus ntsiab lus ntawm wateriness uas yog siv los twv seb cov molecules yog insoluble thaum tso rau hauv dej. Cov ions no tsim ib qho khoom precipitate hauv tag nrhomixes.
txoj cai solubility, tus nqi them
Puas yog nag lossis daus tshwm sim los ntawm txoj cai ntawm cov ntsiab lus dej ntawm cov tshuaj? Qhov tseeb, tag nrho cov kev cai lij choj thiab cov kev xav no muab cov lus qhia uas qhia cov ions uas tsim cov khib nyiab thiab cov uas tseem nyob hauv lawv cov qauv molecular hauv cov kua dej. Cov cai yuav tsum tau ua raws li los ntawm sab saum toj mus rau hauv qab. Qhov no txhais tau hais tias yog tias ib yam dab tsi tsis tuaj yeem txiav txim siab (lossis txiav txim tsis tau) vim yog thawj qhov postulate lawm, nws yuav tsum ua ntej ntawm cov lus qhia ntau dua hauv qab no.
Bromides, chlorides thiab iodides yog soluble.
Cov ntsev uas muaj nag los ntawm cov nyiaj, txhuas thiab mercury tsis tuaj yeem sib xyaw ua ke.
Yog txoj cai hais tias ib qho molecule yog soluble, ces nws tseem nyob rau hauv dej. Tab sis yog hais tias cov khoom yog immiscible raws li txoj cai thiab postulates tau piav saum toj no, ces nws tsim ib tug khoom nrog ib tug khoom los yog kua los ntawm lwm reagent. Yog tias nws tau pom tias tag nrho cov ions hauv cov tshuaj tiv thaiv yog soluble, ces cov txheej txheem nag lossis daus tsis tshwm sim.
Pure ionic equations
Txhawm rau nkag siab lub ntsiab lus ntawm lub tswv yim no, nws yuav tsum nco ntsoov txoj cai rau kev hloov pauv ob zaug, uas tau muab los saum toj no. Vim tias qhov sib xyaw tshwj xeeb no yog txoj kev los nag, cov xeev ntawm cov teeb meem tuaj yeem raug muab rau txhua tus khub sib txawv.
Thawj kauj ruam los sau cov kev sib npaug ionic ntshiab yog cais cov soluble (aqueous) reactants thiab cov khoom rau hauv lawv qhovcations thiab anions. Precipitates tsis yaj hauv dej, yog li tsis muaj cov khoom sib cais. Txoj cai tshwm sim zoo li no.
Hauv kab zauv saum toj no, A + thiab D - ions muaj nyob rau ntawm ob sab ntawm cov qauv. Lawv kuj tseem hu ua spectator molecules vim lawv nyob twj ywm tib yam thoob plaws cov tshuaj tiv thaiv. Vim lawv yog cov uas mus dhau qhov sib npaug tsis hloov. Ntawd yog, lawv tuaj yeem raug cais tawm los qhia cov qauv ntawm qhov tsis zoo molecule.
Qhov sib npaug ionic ntshiab qhia tsuas yog cov nag lossis daus. Thiab lub network molecular mis yuav tsum tau sib npaug ntawm ob sab, tsis tsuas yog los ntawm qhov pom ntawm cov atoms ntawm cov ntsiab lus, tab sis kuj yog tias peb xav txog lawv los ntawm sab ntawm cov nqi hluav taws xob. Cov nag lossis daus feem ntau yog sawv cev tshwj xeeb los ntawm kev sib npaug ionic. Yog hais tias tag nrho cov khoom yog aqueous, cov ntshiab molecular mis tsis tuaj yeem sau. Thiab qhov no tshwm sim vim hais tias tag nrho cov ions raug cais raws li cov khoom ntawm tus saib. Yog li ntawd, tsis muaj nag lossis daus tshwm sim tshwm sim.
Daim ntawv thov thiab piv txwv
Cov tshuaj tiv thaiv nag lossis daus yog qhov tseem ceeb hauv kev txiav txim siab yog tias lub ntsiab lus yog tam sim no hauv kev daws teeb meem. Yog hais tias cov ntaub ntawv precipitate, piv txwv li thaum cov tshuaj reacts nrog cov hlau lead, qhov muaj cov khoom no hauv cov dej tuaj yeem raug kuaj xyuas los ntawm kev ntxiv cov tshuaj thiab saib xyuas qhov tsim ntawm precipitate. Tsis tas li ntawd, kev xav txog sedimentation tuaj yeem siv los rho tawm cov ntsiab lus xws li magnesium los ntawm marinedej. Cov dej nag tshwm sim txawm tshwm sim hauv tib neeg ntawm cov tshuaj tiv thaiv kab mob thiab cov tshuaj tiv thaiv. Txawm li cas los xij, ib puag ncig uas qhov tshwm sim no tseem tab tom kawm los ntawm cov kws tshawb fawb thoob ntiaj teb.
thawj piv txwv
Nws yog qhov tsim nyog los ua kom tiav qhov kev hloov pauv ob zaug, thiab tom qab ntawd txo nws mus rau qhov sib npaug ion ntshiab.
Ua ntej, nws yog qhov tsim nyog los kwv yees cov khoom kawg ntawm cov tshuaj tiv thaiv no siv kev paub txog cov txheej txheem hloov ob. Ua li no, nco ntsoov tias cations thiab anions "hloov cov koom tes".
Thib ob, nws tsim nyog cais cov reagents rau hauv lawv cov ntaub ntawv ionic tag nrho, txij li lawv muaj nyob hauv cov tshuaj aqueous. Thiab tsis txhob hnov qab sib npaug ntawm cov nqi hluav taws xob thiab tag nrho cov atoms.
Thaum kawg, koj yuav tsum suav tag nrho cov neeg saib ions (tib yam molecules uas tshwm sim ntawm ob sab ntawm cov qauv uas tsis tau hloov). Hauv qhov no, cov no yog cov tshuaj xws li sodium thiab chlorine. Qhov kawg ionic equation zoo li no.
Nws tseem yuav tsum ua kom tiav qhov kev hloov pauv ob zaug, thiab tom qab ntawd, dua, nco ntsoov txo nws mus rau qhov sib npaug ntawm ion ntshiab.
kev daws teeb meem dav dav
Cov khoom kwv yees ntawm cov tshuaj tiv thaiv no yog CoSO4 thiab NCL los ntawm cov cai solubility, COSO4 tawg tag vim tias point 4 hais tias sulfates (SO2–4) tsis nyob hauv dej. Ib yam li ntawd, ib qho yuav tsum pom tias NCL tivthaiv tuaj yeem txiav txim siab raws li postulate 1 thiab 3 (tsuas yog thawj nqe lus tuaj yeem raug suav ua pov thawj). Tom qab ntsuas qhov sib npaug, qhov sib npaug tshwm sim muaj daim ntawv hauv qab no.
Rau cov kauj ruam tom ntej, nws tsim nyog cais tag nrho cov khoom rau hauv lawv cov ntawv ionic, vim tias lawv yuav muaj nyob rau hauv cov tshuaj aqueous. Thiab kuj kom sib npaug cov nqi thiab atoms. Tom qab ntawd tshem tawm tag nrho cov neeg saib ions (cov uas tshwm sim raws li cov khoom ntawm ob sab ntawm kab zauv).
Tsis muaj nag lossis daus tshwm sim
Qhov piv txwv tshwj xeeb no yog qhov tseem ceeb vim tias tag nrho cov reactants thiab cov khoom yog aqueous, uas txhais tau hais tias lawv raug cais tawm los ntawm kev sib npaug ionic. Tsis muaj dej nag lossis daus. Yog li ntawd, tsis muaj nag lossis daus tshwm sim.
Nws yog ib qho tsim nyog los sau tag nrho qhov sib npaug ionic rau qhov muaj feem cuam tshuam ob npaug. Nco ntsoov suav nrog lub xeev ntawm qhov teeb meem hauv kev daws teeb meem, qhov no yuav pab kom ua tiav qhov sib npaug hauv cov qauv tag nrho.
Kev daws
1. Txawm hais tias lub cev lub cev, cov khoom ntawm cov tshuaj tiv thaiv no yog Fe (OH) 3 thiab NO3. Cov kev cai solubility kwv yees tias NO3 tawg tag nrho hauv cov kua, vim tias tag nrho cov nitrates ua (qhov no ua pov thawj qhov thib ob). Txawm li cas los xij, Fe (OH) 3 yog insoluble vim tias nag lossis daus ntawm hydroxide ions ib txwm muaj daim ntawv no (raws li cov pov thawj, lub thib rau postulate tuaj yeem muab tau) thiab Fe tsis yog ib qho ntawm cov cations, uas ua rau kev cais tawm ntawm cov khoom. Tom qab dissociation, qhov sib npaug zoo li no:
2. Raws li qhov tshwm sim ntawm kev hloov pauv ob zaug, cov khoom lag luam yog Al, CL3 thiab Ba, SO4, AlCL3 yog soluble vim nws muaj chloride (txoj cai 3). Txawm li cas los xij, B a S O4 tsis decompose hauv cov kua, vim cov khoom muaj sulfate. Tab sis B 2 + ion ua rau nws kuj insoluble, vim nws yogib qho ntawm cov cations uas ua rau muaj kev zam rau txoj cai plaub.
Qhov no yog qhov sib npaug kawg zoo li tom qab ntsuas qhov ntsuas. Thiab thaum cov neeg saib ions raug tshem tawm, cov qauv hauv qab no tau txais.
3. Los ntawm ob qhov kev hloov pauv, HNO3 cov khoom thiab ZnI2 raug tsim. Raws li txoj cai, HNO3 tawg vim nws muaj nitrate (thib ob postulate). Thiab Zn I2 kuj yog soluble vim iodides tib yam (point 3). Qhov no txhais tau hais tias ob yam khoom yog aqueous (uas yog, lawv dissociate nyob rau hauv tej kua) thiab yog li tsis muaj nag lossis daus tshwm sim.
4. Cov khoom ntawm qhov kev hloov pauv ob yog C a3 (PO4) 2 thiab N CL. Txoj Cai 1 hais tias N CL yog soluble, thiab raws li txoj cai thib rau, C a3 (PO4)2 tsis tawg.
Qhov no yog qhov sib npaug ionic yuav zoo li cas thaum cov tshuaj tiv thaiv tiav. Thiab tom qab tshem tawm nag lossis daus, cov qauv no tau txais.
5. Thawj cov khoom ntawm cov tshuaj tiv thaiv no, PbSO4, yog soluble raws li txoj cai plaub vim nws yog sulfate. Cov khoom thib ob KNO3 kuj decomposes hauv cov kua vim nws muaj nitrate (thib ob postulate). Yog li ntawd, tsis muaj nag lossis daus tshwm sim.
txheej txheem tshuaj
Qhov kev txiav txim ntawm kev sib cais cov khoom thaum lub sij hawm los nag los ntawm cov kev daws teeb meem tshwm sim los ntawm kev hloov cov khoom mus rau hauv daim ntawv uas tsis yog-disintegrating, los yog los ntawm kev hloov cov muaj pes tsawg leeg ntawm cov kua.txo qhov zoo ntawm cov khoom hauv nws. Qhov sib txawv ntawm nag lossis daus thiab crystallization feem ntau nyob rau hauv seb qhov tseem ceeb ntawm cov txheej txheem los ntawm kev solubility txo, los yog qhov twg cov qauv ntawm cov khoom tau koom ua ke.
Qee zaum, xaiv nag lossis daus tuaj yeem siv los tshem tawm suab nrov ntawm qhov sib tov. Ib qho tshuaj reagent yog ntxiv rau cov tshuaj thiab nws xaiv reacts nrog kev cuam tshuam los tsim cov dej nag. Nws tuaj yeem raug cais tawm ntawm lub cev los ntawm kev sib xyaw.
Precipitates feem ntau yog siv los tshem tawm cov hlau ions los ntawm cov tshuaj aqueous: nyiaj ions tam sim no hauv cov kua ntsev xws li nyiaj nitrate, uas yog precipitated los ntawm kev ntxiv cov tshuaj chlorine molecules, piv txwv li, uas siv sodium. Cov ions ntawm thawj feem thiab qhov thib ob ua ke los ua cov nyiaj chloride, ib qho chaw uas tsis muaj dej nyob hauv dej. Ib yam li ntawd, barium molecules hloov dua siab tshiab thaum calcium yog precipitated los ntawm oxalate. Cov txheej txheem tau tsim los rau kev tshuaj xyuas ntawm cov khoom sib xyaw ntawm cov hlau ions los ntawm cov ntawv thov sib txuas ntawm cov tshuaj reagents uas precipitate cov tshuaj tshwj xeeb lossis lawv cov pab pawg cuam tshuam.
Nyob rau hauv ntau qhov xwm txheej, txhua yam muaj peev xwm xaiv tau raws li cov khoom siv los ua kom huv thiab yooj yim sib cais. Kev cais cov dej nag thiab txiav txim siab lawv cov huab hwm coj yog txoj hauv kev los nag, nrhiav tus nqi ntawm ntau lub tebchaw.
Thaum sim cais cov khoom los ntawm cov tshuaj uas muaj ntau yam khoom, cov khoom tsis zoo feem ntau muab tso rau hauv cov muaju, txo lawv covpurity thiab degrades qhov tseeb ntawm kev tsom xam. Xws li kev kis kab mob tuaj yeem raug txo los ntawm kev khiav hauj lwm nrog cov tshuaj dilute thiab maj mam ntxiv tus neeg sawv cev precipitating. Cov txheej txheem ua tau zoo yog hu ua homogeneous nag lossis daus, nyob rau hauv uas nws yog synthesized nyob rau hauv kev daws es tsis ntxiv mechanically. Nyob rau hauv cov xwm txheej nyuaj, nws yuav tsum tau cais cov kab mob uas tsis muaj precipitate, re-solve nws, thiab precipitate ib yam nkaus. Feem ntau ntawm cov khoom cuam tshuam tau raug tshem tawm hauv cov khoom qub, thiab qhov kev sim thib ob yog ua tiav thaum lawv tsis tuaj.
Ntxiv rau, lub npe ntawm cov tshuaj tiv thaiv yog muab los ntawm cov khoom tivthaiv, uas yog tsim los ntawm cov tshuaj tiv thaiv nag lossis daus.
txhawm rau cuam tshuam rau kev tawg ntawm cov tshuaj hauv cov khoom sib xyaw, yuav tsum muaj cov nag lossis daus los ua ib qho chaw tsis sib haum, yog tsim los ntawm kev sib cuam tshuam ntawm ob ntsev los yog qhov kub thiab txias.
nag lossis daus ntawm ions no yuav qhia tau tias muaj tshuaj lom neeg cov tshuaj tiv thaiv tau tshwm sim, tab sis nws kuj tuaj yeem tshwm sim yog tias qhov concentration ntawm cov kua dej ntau tshaj nws feem ntawm tag nrho cov kev lwj. Qhov kev txiav txim ua ntej qhov xwm txheej hu ua nucleation. Thaum me me insoluble particles aggregate nrog ib leeg los yog tsim ib tug sab sauv interface nrog ib tug nto xws li lub thawv phab ntsa los yog ib tug noob crystal.
Key Findings: Precipitation in Chemistry
Nyob rau hauv qhov kev tshawb fawb no, cov khoom no yog ob qho lus qhia thiab lub npe. Cov nag lossis daus yog tsim los ntawm qee qhov sib xyaw ua ke, los ntawm kev txo qis kev ua tiav ntawm kev sib xyaw ua ke, lossis los ntawm kev sib cuam tshuam ntawm ob lub ntsev ntsev.
Cov khoom ua tau zoomuaj nuj nqi tseem ceeb. Txij li thaum nws yog tsim los ntawm cov tshuaj tiv thaiv nag lossis daus thiab hu ua precipitate. Cov khoom yog siv los ntxuav, tshem tawm lossis tshem tawm cov ntsev. Thiab tseem rau kev tsim cov pigments thiab kev txheeb xyuas cov khoom hauv kev tshuaj xyuas zoo.
Ntxhais nag los nag, lub tswvyim tswv yim
Terminology tuaj yeem hloov pauv me ntsis. Nov yog nws ua haujlwm li cas: Kev tsim cov khoom los ntawm cov tshuaj hu ua precipitate. Thiab cov tshuaj tiv thaiv uas ua kom muaj zog decomposition hauv cov kua hauv lub xeev hu ua precipitant. Yog hais tias qhov loj me me ntawm cov khoom tsis sib haum xeeb me me, lossis yog tias lub ntiajteb txawj nqus tsis txaus los rub cov crystalline tivthaiv rau hauv qab ntawm lub thawv, cov precipitate yuav sib npaug thoob plaws hauv cov kua, tsim cov slurry. Sedimentation yog hais txog cov txheej txheem uas cais cov sediment los ntawm cov dej ntawm cov tshuaj, uas yog hu ua supernatant. Ib txoj kev sedimentation feem ntau yog centrifugation. Thaum cov nag raug tshem tawm, cov hmoov nplej tuaj yeem hu ua "paj".
Ib qho piv txwv ntawm kev tsim daim ntawv cog lus
Sib tov nyiaj nitrate thiab sodium chloride hauv dej yuav ua rau cov nyiaj chloride los nag tawm ntawm cov tshuaj raws li cov khoom. Ntawd yog, hauv qhov piv txwv no, precipitate yog cov cholesterol.
Thaum sau cov tshuaj tiv thaiv, qhov muaj nag lossis daus tuaj yeem qhia tau los ntawm cov qauv kev tshawb fawb hauv qab no nrog tus xub nqes.
Siv nag los
Cov khoom siv no tuaj yeem siv los txheeb xyuas cov cation lossis anion hauv ntsev ua ib feem ntawm kev tshuaj xyuas zoo. Cov hlau hloov pauv tau paub los ua ntau yam xim precipitate nyob ntawm lawv cov cim keeb thiab oxidation xeev. Kev tiv thaiv nag lossis daus yog siv los tshem cov ntsev ntawm dej. Thiab kuj rau kev xaiv cov khoom thiab rau kev npaj cov pigments. Raws li kev tswj xyuas, cov nag lossis daus cov tshuaj tiv thaiv tsim cov ntshiab precipitate crystals. Nyob rau hauv metallurgy, lawv yog siv los harden alloys.
Yuav ua li cas rov qab sediment
Muaj ntau ntau txoj kev los nag los siv los rho cov khoom:
- Kev lim. Nyob rau hauv qhov kev txiav txim no, cov tshuaj uas muaj cov precipitate yog poured mus rau lub lim. Qhov zoo tshaj plaws, cov khoom tseem nyob ntawm daim ntawv thaum cov kua dhau los ntawm nws. Lub thawv tuaj yeem muab yaug thiab nchuav hla lub lim kom pab rov qab los. Ib txwm muaj qee qhov poob, vim yog kev sib cais hauv cov kua, dhau los ntawm daim ntawv, lossis vim yog adhesion rau cov khoom siv hluav taws xob.
- Centrifugation: Qhov kev txiav txim no tig cov tshuaj sai sai. Rau cov txheej txheem ua hauj lwm, cov khoom precipitate yuav tsum yog denser dua cov kua. Cov densified tivthaiv tuaj yeem tau los ntawm kev nchuav tawm tag nrho cov dej. Feem ntau qhov poob qis dua nrog kev lim dej. Centrifugation ua haujlwm zoo nrog cov qauv me me.
- Kev txiav txim siab: qhov kev txiav txim no nchuav tawm cov kua txheej los yog nqus nws tawm ntawm cov sediment. Qee zaum, ntxiv cov kuab tshuaj ntxiv kom cais cov dej ntawm cov khoom. Decant tuaj yeem siv nrog tag nrho cov khoom tom qab centrifugation.
Ntxawm laus
Ib txheej txheem hu ua digestion tshwm sim thaumcov khoom tshiab tau tso cai nyob hauv nws cov tshuaj. Feem ntau, qhov kub ntawm tag nrho cov kua nce. Improvised digestion tuaj yeem tsim cov khoom loj dua nrog siab purity. Cov txheej txheem uas ua rau qhov tshwm sim no yog hu ua "Ostwald maturation".
