Peb ntsib kev daws teeb meem ntawm ntau yam tshuaj txhua hnub. Tab sis nws tsis zoo li peb txhua tus paub txog lub luag haujlwm loj npaum li cas cov tshuab no ua si. Ntau ntawm lawv tus cwj pwm tau dhau los ua qhov tseeb niaj hnub no los ntawm kev tshawb fawb ntxaws ntau txhiab xyoo. Thaum lub sij hawm tag nrho cov sij hawm no, ntau cov ntsiab lus uas yog incomprehensible rau tus txiv neej ib txwm tau qhia. Ib tug ntawm lawv yog qhov normality ntawm kev daws. Nws yog dab tsi? Qhov no yuav tau tham hauv peb tsab xov xwm. Cia peb pib los ntawm kev dhia mus rau yav dhau los.
Kev tshawb fawb keeb kwm
Thawj lub siab ci ntsa iab uas pib kawm cov kev daws teeb meem yog cov kws paub zoo xws li Arrhenius, van't Hoff thiab Ostwald. Raws li kev cuam tshuam ntawm lawv txoj haujlwm, tiam tom ntej ntawm chemists pib delve rau hauv txoj kev tshawb fawb ntawm aqueous thiab dilute daws. Tau kawg, lawv tau sau ntau qhov kev paub, tab sis cov kev daws teeb meem tsis muaj dej tau tso tseg yam tsis muaj kev saib xyuas, uas, los ntawm txoj kev, kuj ua lub luag haujlwm tseem ceeb hauv kev lag luam thiab lwm qhov chaw ntawm tib neeg lub neej.
Muaj ntau qhov kev nkag siab tsis tau hauv txoj kev xav ntawm cov kev daws teeb meem tsis muaj dej. Piv txwv li, yog hais tias nyob rau hauv aqueous systems, tus nqi ntawm conductivity nce nrog ib tug nce nyob rau hauv lub degree ntawm dissociation, ces nyob rau hauv zoo sib xws systems, tab sis nrog ib tug sib txawv hnyav es tsis txhob dej, nws yog lwm txoj kev nyob ib ncig ntawm. Cov nqi hluav taws xob me meconductivities feem ntau sib haum mus rau high degree ntawm dissociation. Anomalies tau txhawb cov kws tshawb fawb los tshawb txog thaj tsam ntawm chemistry. Ib tug loj array ntawm cov ntaub ntawv tau sau, qhov kev ua ntawm uas ua rau nws muaj peev xwm mus nrhiav tau raws li niaj zaus uas ntxiv cov kev xav ntawm electrolytic dissociation. Tsis tas li ntawd, nws muaj peev xwm nthuav dav kev paub txog electrolysis thiab qhov xwm ntawm complex ions ntawm cov organic thiab inorganic compounds.
Tom qab ntawd kev tshawb fawb ntxiv tau pib hauv thaj chaw ntawm cov kev daws teeb meem. Cov tshuab no sib txawv hauv cov khoom los ntawm cov dilute vim qhov tseeb tias nrog kev nce siab ntawm cov tshuaj yaj, nws cov kev cuam tshuam nrog cov kuab tshuaj pib ua lub luag haujlwm tseem ceeb. Xav paub ntxiv txog qhov no hauv ntu tom ntej.
Theory
Tam sim no, qhov kev piav qhia zoo tshaj plaws ntawm tus cwj pwm ntawm ions, molecules thiab atoms hauv kev daws tsuas yog txoj kev xav ntawm electrolytic dissociation. Txij li thaum nws tsim los ntawm Svante Arrhenius nyob rau hauv lub xyoo pua 19th, nws tau hloov pauv qee yam. Qee cov kev cai lij choj tau pom (xws li Ostwald's dilution law) uas qee yam tsis haum rau hauv txoj kev xav classical. Tab sis, ua tsaug rau cov haujlwm tom ntej ntawm cov kws tshawb fawb, tau hloov kho rau txoj kev xav, thiab hauv nws daim ntawv niaj hnub nws tseem muaj thiab piav qhia txog cov txiaj ntsig tau sim nrog qhov raug siab.
Lub ntsiab tseem ceeb ntawm txoj kev xav ntawm electrolytic dissociation yog cov khoom, thaum yaj, decomposes rau hauv nws cov ions - cov khoom uas muaj nqi. Nyob ntawm qhov muaj peev xwm decompose (dissociate) rau hauv qhov chaw, muaj zog thiab tsis muaj zogelectrolytes. Cov muaj zog muaj peev xwm ua kom tiav rau hauv ions hauv kev daws, thaum cov tsis muaj zog tsuas yog me me xwb.
Cov khoom no uas cov molecule tawg tuaj yeem cuam tshuam nrog cov kuab tshuaj. Qhov tshwm sim no hu ua kev daws teeb meem. Tab sis nws tsis yog ib txwm tshwm sim, vim nws yog vim muaj cov nqi ntawm cov ion thiab hnyav molecules. Piv txwv li, ib tug dej molecule yog ib tug dipole, uas yog, ib tug particle nqi zoo ntawm ib sab thiab tsis zoo them rau lwm yam. Thiab cov ions uas cov electrolyte decomposes kuj muaj nqi. Yog li, cov khoom no yog attracted los ntawm oppositely them sab. Tab sis qhov no tshwm sim tsuas yog nrog polar solvents (xws li dej). Piv txwv li, nyob rau hauv ib qho kev daws ntawm ib yam khoom nyob rau hauv hexane, kev daws yuav tsis tshwm sim.
Tau kawm cov kev daws teeb meem, nws yog ib qho tsim nyog yuav tsum paub ntau npaum li cas ntawm cov kua. Qee zaum nws tsis yooj yim heev los hloov qee qhov ntau rau hauv cov qauv. Yog li ntawd, muaj ntau ntau hom concentrations, uas yog cov normality ntawm cov tshuaj. Tam sim no peb yuav qhia meej txog txhua txoj hauv kev ntawm kev nthuav tawm cov ntsiab lus ntawm cov khoom hauv kev daws teeb meem thiab cov txheej txheem rau kev suav nws.
Txoj kev daws teeb meem
Muaj ntau cov qauv hauv chemistry, thiab qee qhov ntawm lawv yog tsim los ntawm kev ua kom yooj yim dua rau kev coj tus nqi hauv ib daim ntawv lossis lwm yam.
Thawj, thiab paub zoo tshaj rau peb, daim ntawv qhia ntawm kev xav yog qhov feem ntau. Nws yog xam yooj yim heev. Peb tsuas yog yuav tsum tau faib qhov loj ntawm cov khoom hauv kev daws los ntawm nws qhov loj tag nrho. Yog liYog li, peb tau txais cov lus teb hauv feem ntawm ib qho. Muab tus lej tshwm sim los ntawm ib puas, peb tau txais cov lus teb raws li feem pua.
Daim ntawv me me uas tsis paub yog qhov ntim feem. Feem ntau nws yog siv los qhia qhov concentration ntawm cawv hauv cov dej cawv. Nws kuj yog xam tau yooj yim heev: peb faib lub ntim ntawm cov kua los ntawm lub ntim ntawm tag nrho cov tov. Raws li nyob rau hauv rooj plaub dhau los, koj tuaj yeem tau txais cov lus teb raws li feem pua. Cov ntawv lo feem ntau hais tias: "40% vol.", uas txhais tau tias: 40 ntim feem pua.
Nyob rau hauv chemistry, lwm hom concentration feem ntau yog siv. Tab sis ua ntej mus rau lawv, cia peb tham txog dab tsi mole ntawm ib yam khoom yog dab tsi. Tus nqi ntawm cov khoom muaj peev xwm qhia tau ntau yam: loj, ntim. Tab sis tom qab tag nrho, cov molecules ntawm txhua yam khoom muaj lawv tus kheej qhov hnyav, thiab los ntawm qhov loj ntawm cov qauv nws tsis yooj yim sua kom nkag siab tias muaj pes tsawg molecules nyob rau hauv nws, thiab qhov no yog qhov tsim nyog kom nkag siab txog qhov ntau ntawm cov tshuaj hloov pauv. Rau qhov no, xws li ib tug ntau npaum li ib tug mole ntawm ib yam khoom tau qhia. Qhov tseeb, ib qho mole yog ib qho ntawm cov molecules: 6.021023. Qhov no hu ua Avogadro tus lej. Feem ntau, xws li ib chav tsev li mole ntawm ib yam khoom yog siv los xam tus nqi ntawm cov khoom ntawm cov tshuaj tiv thaiv. Nyob rau hauv no hais txog, muaj lwm hom kev qhia concentration - molarity. Qhov no yog tus nqi ntawm cov khoom rau ib chav tsev ntim. Molarity qhia hauv mol/L (nyeem: moles ib liter).
Muaj ib hom kev qhia zoo sib xws rau cov ntsiab lus ntawm cov khoom hauv ib qho system: molality. Nws txawv ntawm molarity nyob rau hauv uas nws txiav txim siab npaum li cas ntawm cov khoom tsis nyob rau hauv ib chav tsev ntawm ntim, tab sis nyob rau hauv ib chav tsev ntawm loj. Thiab qhia nyob rau hauv kev thov Vajtswvib kilogram (los yog lwm yam ntau, xws li ib gram).
Yog li peb tuaj rau daim ntawv kawg, uas tam sim no peb yuav sib tham nyias, vim nws cov lus piav qhia yuav tsum muaj qee cov ntaub ntawv theoretical.
daws normality
Qhov no yog dab tsi? Thiab nws txawv li cas ntawm cov nqi yav dhau los? Ua ntej koj yuav tsum nkag siab qhov txawv ntawm cov ntsiab lus xws li normality thiab molarity ntawm kev daws. Qhov tseeb, lawv txawv ntawm ib qho nqi - tus lej sib npaug. Tam sim no koj tuaj yeem xav txog seb qhov normality ntawm cov tshuaj yog dab tsi. Nws tsuas yog hloov molarity xwb. Tus lej sib npaug qhia tau hais tias muaj pes tsawg tus hais tuaj yeem cuam tshuam nrog ib lub mole ntawm hydrogen ions lossis hydroxide ions.
Peb tau paub txog qhov zoo li cas ntawm kev daws. Tab sis tom qab tag nrho, nws tsim nyog khawb tob, thiab peb yuav pom qhov yooj yim npaum li cas, thaum xub thawj siab ib muag, complex daim ntawv piav qhia txog concentration yog. Yog li, cia peb mus saib seb qhov normality ntawm kev daws yog dab tsi.
Formula
Nws yooj yim zoo nkauj los xav txog cov qauv ntawm cov lus piav qhia. Nws yuav zoo li no: Cn=zn/N. Ntawm no z yog qhov sib npaug, n yog tus nqi ntawm cov khoom, V yog qhov ntim ntawm cov tshuaj. Thawj tus nqi yog qhov nthuav tshaj plaws. Nws tsuas yog qhia qhov sib npaug ntawm cov khoom, uas yog, tus naj npawb ntawm cov khoom tiag lossis cov lus xav uas tuaj yeem hnov mob nrog ib qho me me ntawm lwm yam khoom. Los ntawm qhov no, qhov tseeb, qhov normality ntawm kev daws, cov qauv uas tau nthuav tawm saum toj no, zoo sib txawv.los ntawm molarity.
Thiab tam sim no cia peb mus rau lwm qhov tseem ceeb: yuav ua li cas txiav txim siab qhov qub ntawm cov tshuaj. Qhov no yog undoubtedly ib lo lus nug tseem ceeb, yog li nws yog tsim nyog los mus rau nws txoj kev kawm nrog kev nkag siab ntawm txhua tus nqi qhia nyob rau hauv kab zauv uas tau hais los saum toj no.
Yuav ua li cas thiaj nrhiav tau qhov normality ntawm kev daws?
Cov mis uas peb tham saum toj no yog siv dawb huv. Tag nrho cov txiaj ntsig tau muab rau hauv nws tau yooj yim xam hauv kev xyaum. Qhov tseeb, nws yog ib qho yooj yim heev los xam cov normality ntawm ib qho kev daws, paub qee qhov ntau: qhov loj ntawm cov kua, nws cov mis thiab qhov ntim ntawm cov tshuaj. Txij li thaum peb paub cov qauv ntawm cov molecules ntawm ib yam khoom, peb tuaj yeem pom nws qhov hnyav molecular. Qhov sib piv ntawm qhov loj ntawm ib qho piv txwv ntawm ib qho kev daws rau nws cov molar loj yuav sib npaug rau tus naj npawb ntawm moles ntawm cov khoom. Thiab paub qhov ntim ntawm tag nrho cov tshuaj, peb tuaj yeem hais kom paub tseeb tias peb cov molar concentration yog dab tsi.
Txoj haujlwm tom ntej uas peb yuav tsum tau ua txhawm rau txhawm rau xam qhov qub ntawm kev daws yog qhov kev txiav txim ntawm kev nrhiav qhov sib npaug. Txhawm rau ua qhov no, peb yuav tsum nkag siab tias muaj pes tsawg cov khoom raug tsim los ntawm kev sib cais uas tuaj yeem txuas cov protons lossis hydroxyl ions. Piv txwv li, nyob rau hauv sulfuric acid, qhov sib npaug yog 2, thiab yog li ntawd qhov normality ntawm cov tshuaj nyob rau hauv cov ntaub ntawv no yog xam los ntawm tsuas yog muab nws molarity los ntawm 2.
Daim ntawv thov
Hauv tshuaj analytics, ib qho feem ntau yuav tsum xam qhov normality thiab molarity ntawm kev daws. Qhov no yooj yim heev rauKev suav cov qauv molecular ntawm cov khoom.
Yuav nyeem dab tsi?
Kom nkag siab zoo dua qhov qub ntawm kev daws teeb meem yog dab tsi, nws yog qhov zoo tshaj los qhib phau ntawv qhia txog chemistry. Thiab yog tias koj twb paub tag nrho cov ntaub ntawv no, koj yuav tsum xa mus rau phau ntawv qhia txog kev tshuaj ntsuam chemistry rau cov tub ntxhais kawm ntawm cov tshuaj tshwj xeeb.
Zoo kawg
Ua tsaug rau tsab xov xwm, peb xav tias koj nkag siab tias qhov qub ntawm cov tshuaj yog ib hom kev qhia txog cov ntsiab lus ntawm cov tshuaj, uas yog siv feem ntau hauv kev tshuaj xyuas tshuaj. Thiab tam sim no nws tsis yog qhov zais cia rau leej twg yuav suav li cas.
