Kev daws, nrog rau cov txheej txheem ntawm lawv tsim, yog qhov tseem ceeb hauv ntiaj teb ib puag ncig peb. Dej thiab huab cua yog ob ntawm lawv cov neeg sawv cev, yam tsis muaj lub neej hauv ntiaj teb ua tsis tau. Cov kua roj ntsha feem ntau hauv cov nroj tsuag thiab tsiaj txhu kuj yog kev daws teeb meem. Cov txheej txheem ntawm kev zom zaub mov yog inextricably txuas nrog kev sib cais ntawm cov as-ham.
Ib qho kev tsim khoom yog cuam tshuam nrog kev siv qee yam kev daws teeb meem. Lawv siv nyob rau hauv textile, zaub mov, tshuaj, metalworking, mining, plastics thiab fiber ntau industries. Yog li ntawd nws yog ib qho tseem ceeb kom nkag siab tias lawv yog dab tsi, kom paub lawv cov khoom thiab qhov txawv qhov txawv.
Cov cim qhia tseeb
Cov kev daws tau nkag siab tias cov txheej txheem sib xyaw ua ke tau tsim thaum lub sijhawm faib ntawm ib feem ntawm lwm qhov. Lawv tseem hu ua dispersed systems, uas, nyob ntawm seb qhov loj ntawm cov khoom uas tsim lawv, muab faib ua colloidal systems, suspensions thiab cov ntsiab lus tseeb.
Nyob rau tom kawg, cov khoom nyob rau hauv lub xeev ntawm kev sib cais rau hauv molecules, atoms los yog ions. Xws li cov tshuab molecular-dispersed yog cov yam ntxwv ntawm cov hauv qab no:
Y
Nyob zoo ib tsoom phooj ywg;
Hauv lwm lo lus, lawv tuaj yeem tsim tau yog tias muaj kev sib cuam tshuam ntawm cov khoom, uas ua rau kev sib cais ntawm cov tshuaj mus rau hauv cov khoom me me yam tsis muaj kev siv zog sab nraud. Cov kev daws teeb meem yuav tsum yog ib theem, uas yog, yuav tsum tsis muaj qhov sib cuam tshuam ntawm cov khoom siv. Qhov kawg kos npe yog qhov tseem ceeb tshaj plaws, txij li cov txheej txheem kev sib cais tuaj yeem ua tiav spontaneously yog tias nws muaj zog txaus rau lub cev. Nyob rau hauv cov ntaub ntawv no, lub free zog txo, thiab lub system ua equilibrium. Nrog rau tag nrho cov nta no, peb tuaj yeem tsim cov ntsiab lus hauv qab no:
Kev daws qhov tseeb yog qhov sib npaug ruaj khov ntawm kev sib cuam tshuam ntawm ob lossis ntau yam khoom, qhov loj ntawm qhov tsis pub tshaj 10 -7 cm, uas yog, lawv yog qhov sib npaug. Nrog atoms, molecules thiab ions.
Ib qho ntawm cov tshuaj yog cov kuab tshuaj (raws li txoj cai, qhov no yog cov khoom uas nws cov concentration siab dua), thiab cov solutes. Yog hais tias cov khoom qub nyob rau hauv ntau lub xeev ntawm kev sib sau, ces cov kuab tshuaj yog coj raws li ib qho uas tsis hloov nws.
Yam kev daws teeb meem
Raws li lub xeev ntawm kev sib sau, cov kev daws teeb meem yog kua, gaseous thiab khoom. Cov tshuab ua kua yog qhov ntau tshaj plaws, thiab lawv kuj tau muab faib ua ntau hom nyob ntawm qhov pib lub xeev.solute:
- khoom hauv kua, zoo li qab zib lossis ntsev hauv dej;
- kua hauv kua, xws li sulfuric lossis hydrochloric acid hauv dej;
- gaseous rau kua, zoo li oxygen lossis carbon dioxide hauv dej.
Txawm li cas los xij, tsis tsuas yog dej tuaj yeem ua kuab tshuaj. Thiab los ntawm qhov xwm txheej ntawm cov kuab tshuaj, tag nrho cov kua daws tau muab faib ua aqueous, yog tias cov tshuaj tau yaj hauv dej, thiab tsis muaj dej, yog tias cov tshuaj tau yaj hauv ether, ethanol, benzene, thiab lwm yam.
Raws li hluav taws xob conductivity, cov kev daws teeb meem tau muab faib ua electrolytes thiab non-electrolytes. Electrolytes yog cov tebchaw nrog feem ntau ionic crystalline daim ntawv cog lus, uas, thaum dissociated nyob rau hauv kev daws, tsim ions. Thaum yaj, uas tsis yog-electrolytes tawg rau hauv atoms lossis molecules.
Hauv cov kev daws teeb meem tiag tiag, ob txoj haujlwm sib txawv tshwm sim ib txhij - kev sib cais ntawm cov khoom thiab nws cov crystallization. Nyob ntawm txoj haujlwm ntawm qhov sib npaug hauv "kev daws teeb meem" qhov system, cov kev daws teeb meem hauv qab no yog qhov txawv:
- saturated, thaum tus nqi ntawm kev sib cais ntawm ib yam khoom yog sib npaug rau tus nqi ntawm nws tus kheej crystallization, uas yog, cov tshuaj nyob rau hauv equilibrium nrog cov hnyav;
- unsaturated yog tias lawv muaj cov kuab tshuaj tsawg dua saturated ntawm tib qhov kub;
- supersaturated, uas muaj ntau tshaj ntawm cov kuab tshuaj nyob rau hauv kev sib piv nrog ib tug saturated, thiab ib tug crystal ntawm nws yog txaus los pib active crystallization.
Raws li qhov ntaucov yam ntxwv, xav txog cov ntsiab lus ntawm ib qho kev tivthaiv hauv kev daws teeb meem, siv cov concentration. Cov kev daws teeb meem nrog cov ntsiab lus qis ntawm cov ntsiab lus yog hu ua dilute, thiab nrog cov ntsiab lus siab - concentrated.
Txoj Kev Qhia Kom Paub
Mass feem (ω) - qhov loj ntawm cov khoom (mv-va), xa mus rau qhov loj ntawm cov tshuaj (mp-ra). Hauv qhov no, qhov loj ntawm cov tshuaj yog muab raws li qhov sib npaug ntawm qhov loj ntawm cov khoom thiab cov hnyav (mp-la).
Mole feem (N) - tus naj npawb ntawm moles ntawm ib tug solute (Nv-va) muab faib los ntawm tag nrho cov moles ntawm cov tshuaj uas tsim ib tug tov (ΣN).
Molality (Cm) - tus naj npawb ntawm moles ntawm ib qho solute (Nv-va) muab faib los ntawm qhov hnyav ntawm cov kuab tshuaj (m r-la).
Molar concentration (Cm) - qhov loj ntawm cov solute (mv-va) xa mus rau qhov ntim ntawm tag nrho cov tshuaj (V).
Normalality, los yog sib npaug concentration, (Cn) - tus naj npawb ntawm qhov sib npaug (E) ntawm cov kuab tshuaj, xa mus rau qhov ntim ntawm cov tshuaj.
Titer (T) - qhov loj ntawm ib yam khoom (m in-va) yaj hauv ib lub ntim ntawm cov tshuaj.
Volume fraction (ϕ) of a gaseous substance - lub ntim ntawm cov khoom (Vv-va) faib los ntawm qhov ntim ntawm cov tshuaj (V p-ra).
Txoj kev daws teeb meem
Xav txog qhov teeb meem no, feem ntau lawv tham txog dilute cov ntsiab lus ntawm cov tsis yog electrolytes. Qhov no yog vim, ua ntej, rau qhov tseeb tias qhov kev sib cuam tshuam ntawm cov khoom ua rau lawv los ze zog rau cov roj zoo tagnrho. Thiab thib ob,lawv cov khoom yog vim muaj kev sib tshuam ntawm txhua qhov hais thiab yog proportional rau cov ntsiab lus ntawm cov khoom. Xws li cov khoom ntawm cov ntsiab lus tseeb yog hu ua colligative. Lub vapor siab ntawm cov kuab tshuaj tshaj li cov tshuaj tau piav qhia los ntawm Raoult txoj cai, uas tau hais tias qhov txo qis hauv vapor siab ntawm cov kuab tshuaj ΔР tshaj cov tshuaj yog ncaj qha proportional rau molar feem ntawm cov kua (T v- va) thiab lub vapor siab tshaj cov kuab tshuaj ntshiab (R0r-la):
ΔР=Рor-la∙ Tv-va
Qhov nce hauv cov ntsiab lus kub ΔТк thiab cov ntsiab lus khov ΔТз ntawm cov kev daws teeb meem ncaj qha rau cov molar concentrations ntawm cov tshuaj yaj hauv lawv Сm:
ΔTk=E ∙ Cm, qhov twg E yog qhov ebullioscopic tas li;
ΔTz=K ∙ Cm, qhov twg K yog qhov ntsuas qhov qub.
Osmotic siab π yog xam los ntawm kab zauv:
π=R∙E∙Xv-va / Vr-la, qhov Xv-va yog cov feem molar ntawm tus solute, Vr-la yog qhov ntim ntawm cov kuab tshuaj.
Qhov tseem ceeb ntawm kev daws teeb meem hauv lub neej niaj hnub ntawm txhua tus neeg yog qhov nyuaj rau overestimate. Cov dej ntuj muaj cov roj ntsha uas yaj - CO2 thiab O2, ntau cov ntsev - NaCl, CaSO4, MgCO3, KCl, thiab lwm yam. Tab sis tsis muaj cov impurities hauv Lub cev tuaj yeem cuam tshuam cov dej ntsev metabolism thiab kev ua haujlwm ntawm cov hlab plawv. Lwm qhov piv txwv ntawm cov kev daws teeb meem tseeb yog cov hlau alloy. Nws tuaj yeem yog tooj dag lossis cov hniav nyiaj hniav kub kub, tab sis, qhov tseem ceeb tshaj, tom qab sib tovmelted Cheebtsam thiab txias ntawm lub resulting tov, ib theem khoom yog tsim. Cov hlau alloys yog siv nyob txhua qhov chaw, los ntawm cutlery mus rau electronics.
