3 Txoj Hauv Kev Los Lej Vapor Siab

Cov txheej txheem:

3 Txoj Hauv Kev Los Lej Vapor Siab
3 Txoj Hauv Kev Los Lej Vapor Siab

Video: 3 Txoj Hauv Kev Los Lej Vapor Siab

Video: 3 Txoj Hauv Kev Los Lej Vapor Siab
Video: Nraug txuj kev hlub 2024, Lub peb hlis ntuj
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Koj puas tau tso lub raj mis dej hauv lub hnub ci rau ob peb teev, tsuas yog hnov me ntsis "xuav" thaum koj qhib nws dua? Qhov tshwm sim no tshwm sim los ntawm txoj cai hu ua pa siab. Hauv kev siv tshuaj lom neeg, lub siab ua pa yog lub siab ua rau ntawm phab ntsa ntawm lub thawv kaw thaum cov khoom muaj nyob hauv nws evaporates rau roj. Txhawm rau nrhiav cov pa siab ntawm qhov ntsuas kub, siv Clausius-Clapeyron sib npaug: ln (P1/P2) = (ΔHvap ua/R) ((1/T2) - (1/T1)).

cov kauj ruam

Txoj Kev 1 ntawm 3: Siv Clausius-Clapeyron Equation

Xam Cov Vapor Siab Kauj Ruam 1
Xam Cov Vapor Siab Kauj Ruam 1

Kauj Ruam 1. Sau Clausius-Clapeyron equation

Cov mis siv hauv kev suav lub siab ua pa, muab qee qhov kev hloov pauv hauv lub siab uas twb muaj lawm, hu ua Clausius-Clapeyron equation (muaj npe tom qab kws kho mob Rudolf Clausius thiab Benoît Paul Émile Clapeyron). Qhov no feem ntau yog cov qauv xav tau txhawm rau tshawb pom qhov ua rau muaj teeb meem vapor feem ntau pom nyob hauv phau ntawv physics thiab chemistry. Nws tau sau raws li hauv qab no: ln (P1/P2) = (ΔHvap ua/R) ((1/T2) - (1/T1)). Hauv cov qauv no, cov kev hloov pauv hais txog cov hloov pauv hauv qab no:

  • - Hvap ua:

    enthalpy ntawm cov kua ua pa. Tus nqi no feem ntau tuaj yeem pom hauv lub rooj nyob tom qab ntawm phau ntawv tshuaj lom neeg.

  • A:

    cov ntsiab lus roj tiag, lossis 8.314 J / (K × mol).

  • T1:

    qhov ntsuas kub uas paub lub siab ua pa (lossis thawj qhov kub).

  • T2:

    qhov ntsuas kub uas yuav tsum pom cov pa (lossis qhov kub kawg).

  • P1 / P2:

    ua pa nyuaj ntawm qhov kub T1 thiab T2, feem.

Xam Cov Vapor Siab Kauj Ruam 2
Xam Cov Vapor Siab Kauj Ruam 2

Kauj Ruam 2. Nkag mus paub qhov sib txawv

Clausius-Clapeyron equation zoo li nyuaj muab plethora ntawm ntau qhov sib txawv, tab sis nws yeej tsis nyuaj thaum muaj cov ntaub ntawv raug. Qhov teeb meem ua pa yooj yim tshaj plaws yuav muab ob qhov txiaj ntsig txheeb ze rau qhov kub thiab ib tus txheeb ze rau qhov siab, lossis ob tus txheeb ze rau qhov siab thiab ib tus txheeb ze rau qhov kub thiab txias - thaum lawv nyob tam sim no, daws qhov teeb meem yuav yooj yim.

  • Piv txwv li, cia peb hais tias peb muaj lub taub ntim puv kua ntawm qhov kub ntawm 295 K, uas nws cov pa siab sib npaug li 1 atm. Cov lus nug yog: Dab tsi yog qhov pa ntawm qhov kub ntawm 393 K? Peb muaj ob qhov ntsuas kub thiab ib qho rau siab, yog li peb tuaj yeem daws qhov teeb meem nrog Clausius-Clapeyron equation. Inserting the variables, peb yuav muaj: ln (1/P2) = (ΔHvap ua/R) ((1/393) - (1/295))
  • Nco tseg tias hauv Clausius-Clapeyron sib npaug nws yuav tsum tau nkag mus rau qhov ntsuas kub hauv qib Kelvin. Koj tuaj yeem siv qhov ntsuas qhov ntsuas tau ntev li ntev tau lawv nyob hauv cov chav zoo ib yam hauv P1 thiab P2.
Xam Cov Vapor Siab Kauj Ruam 3
Xam Cov Vapor Siab Kauj Ruam 3

Kauj Ruam 3. Nkag mus rau qhov tsis sib xws

Clausius-Clapeyron equation muaj ob qhov sib xws: R thiab ΔHvap ua. R yog ib txwm sib npaug rau 8.314 J / (K × mol). Tus nqi ntawm ΔHvap ua (enthalpy ntawm vaporization), txawm li cas los xij, nyob ntawm cov khoom uas nws lub siab ua pa raug tshuaj xyuas. Raws li tau hais ua ntej, koj tuaj yeem pom qhov tseem ceeb rau ΔHvap ua ntawm ntau yam tshuaj nyob rau sab nraub qaum ntawm tshuaj lom neeg lossis phau ntawv physics, lossis online (xws li ntawm no).

  • Hauv peb qhov piv txwv, cia peb hais tias peb cov kua muaj dej ntshiab huv. Yog tias peb saib hauv lub rooj ntawm valuesH qhov tseem ceebvap ua, peb yuav pom tias ΔHvap ua yuav kwv yees kwv yees li 40, 65 KJ / mol. Txij li peb tus nqi rau H siv joules, peb tuaj yeem hloov tus lej pom rau 40,650 J/mol.
  • Ntxig qhov txuas rau hauv peb qhov kev ua zauv, peb yuav muaj: ln (1/P2) = (40,650/8, 314) ((1/393) - (1/295)).
Xam Cov Vapor Siab Kauj Ruam 4
Xam Cov Vapor Siab Kauj Ruam 4

Kauj Ruam 4. Txhim kho qhov sib npaug

Thaum koj muaj tag nrho cov kev hloov pauv nkag mus rau qhov sib npaug tshwj tsis yog ib qho uas yuav tsum tau tshawb pom, npaj los ntawm kev daws nws raws li cov cai ntawm algebra.

  • Tsuas yog ib qho nyuaj ntawm qhov kev ua zauv - ln (1/P2) = (40,650/8, 314) ((1/393) - (1/295)) - yog cuam tshuam nrog lub ntuj logarithm (ln). Txhawm rau tshem nws, tsuas yog siv ob sab ntawm qhov kev ua zauv raws li cov lus piav qhia rau zauv zauv tas li e. Ua lwm yam lus: ln (x) = 2 → thiabln (x) = thiab2 → x = thiab2.
  • Tam sim no, cia peb daws qhov sib npaug:

    • ln (1/P2) = (40,650/8, 314) ((1/393) - (1/295))
    • ln (1/P2) = (4,889, 34) (-0, 00084)
    • (1/P2) = thiab(-4, 107)
    • 1/P2 = 0.0165
    • P2 = 0.0165-1 = 60, 76 awm. Qhov no ua rau kev nkag siab - hauv lub thawv kaw, nce qhov kub tam sim no los ntawm yuav luag 100 degrees (txog li 20 degrees saum toj no cov dej kub npau npau) yuav tsim kom muaj cov pa loj heev, ua rau nce siab sab hauv.

Txoj Kev 2 ntawm 3: Nrhiav Vapor Siab nrog Dissolved Solutions

Xam Cov Vapor Siab Kauj Ruam 5
Xam Cov Vapor Siab Kauj Ruam 5

Kauj Ruam 1. Sau Raoult Txoj Cai

Hauv lub neej tiag, nws tsis tshua ua haujlwm nrog ib leeg kua ntshiab - peb feem ntau cuam tshuam nrog cov kua ua los ntawm kev sib xyaw ntawm cov tshuaj sib txawv. Qee qhov feem ntau ntawm cov no yog tsim los ntawm kev yaj me me ntawm qee yam tshuaj hu ua solute rau hauv cov tshuaj loj hu ua hnyav, yog li tsim kev daws teeb meem. Hauv cov xwm txheej no, nws yog qhov muaj txiaj ntsig kom paub qhov sib npaug hu ua Raoult's Law (tom qab kws kho mob kws kho mob François-Marie Raoult), uas zoo li cov hauv qab no: RAUkev daws teeb meem = Pebhnyav × xwmhnyav. Hauv cov mis no, cov hloov pauv hais txog:

  • RAUkev daws teeb meem:

    lub siab ua pa ntawm tag nrho cov kev daws teeb meem (txhua feem sib xyaw ua ke).

  • RAUhnyav:

    vapor siab ntawm qhov hnyav.

  • Xhnyav:

    qhov molar feem ntawm qhov hnyav.

  • Tsis txhob txhawj xeeb yog tias koj tsis paub cov ntsiab lus zoo li "mole feem" - lawv yuav piav qhia hauv cov kauj ruam tom ntej.
Xam Cov Vapor Siab Kauj Ruam 6
Xam Cov Vapor Siab Kauj Ruam 6

Kauj Ruam 2. Txheeb xyuas cov kuab tshuaj thiab cov tshuaj nyob hauv cov tshuaj

Ua ntej xam cov pa siab ntawm cov kua sib xyaw, koj yuav tsum txheeb xyuas cov tshuaj koj tab tom ua haujlwm nrog. Nws yog ib qho tseem ceeb kom nco ntsoov tias kev daws teeb meem tau tsim thaum cov kuab tshuaj tau yaj hauv cov kuab tshuaj - cov tshuaj yaj yog ib txwm daws, thiab cov tshuaj uas yaj yog ib txwm hnyav.

  • Peb yuav ua haujlwm dhau qhov piv txwv yooj yim los qhia txog cov ntsiab lus uas yuav tham. Piv txwv li, cia peb hais tias peb tau tsom mus nrhiav qhov ua pa ntawm cov kua ntau. Kev lig kev cai, cov khoom no suav nrog ib feem ntawm cov piam thaj yaj hauv ib feem ntawm cov dej, yog li ntawd qab zib yog cov kuab tshuaj thiab dej cov kuab tshuaj.
  • Nco ntsoov tias cov tshuaj lom rau sucrose (cov piam thaj ntau) yog C.12H22O11. Nws yuav yog qhov tseem ceeb sai sai no
Xam Cov Vapor Siab Kauj Ruam 7
Xam Cov Vapor Siab Kauj Ruam 7

Kauj Ruam 3. Tshawb nrhiav qhov ntsuas kub ntawm qhov kev daws teeb meem

Raws li pom hauv ntu Clausius-Clapeyron saum toj no, qhov kub ntawm cov kua yuav cuam tshuam nws cov pa siab. Feem ntau hais lus, qhov kub siab dua, ntau dua qhov ua pa siab - raws li qhov kub tau nce, ntau cov kua yuav yaj, ua pa thiab ua rau lub siab sab hauv ntawm lub nkoj.

Hauv peb qhov piv txwv, cia peb hais tias qhov ntsuas kub tam sim no ntawm cov kua phoov yog sib npaug 298k ua (kwv yees li 25 ° C).

Xam Cov Vapor Siab Kauj Ruam 8
Xam Cov Vapor Siab Kauj Ruam 8

Kauj Ruam 4. Tshawb xyuas qhov hnyav ntawm cov pa hnyav

Cov ntaub ntawv siv tshuaj lom neeg feem ntau qhia qhov ua pa siab rau tus lej ntawm cov sib txuas sib xyaw thiab cov tshuaj, tab sis feem ntau lawv yuav nthuav tawm ntawm qhov kub ntawm 25 ° C (298 K) lossis lawv cov ntsiab lus kub. Yog tias kev daws teeb meem yog ntawm ib qho ntawm qhov ntsuas kub no, koj tuaj yeem siv tus nqi siv. Yog tias tsis yog, koj yuav tsum paub qhov ua pa ntawm koj qhov ntsuas kub tam sim no.

  • Kev sib raug zoo ntawm Clausius -Clapeyron tuaj yeem pab nyob rau lub sijhawm no - siv qhov ntsuas qhov ntsuas siab thiab 298 K (25 ° C) rau P1 thiab T1, feem.
  • Hauv peb qhov piv txwv qhov sib xyaw yog ntawm 25 ° C yog li peb tuaj yeem siv cov lus siv. Peb pom tias dej ntawm 25 ° C muaj cov pa siab sib npaug 23, 8 hli Hg.
Xam Cov Vapor Siab Kauj Ruam 9
Xam Cov Vapor Siab Kauj Ruam 9

Kauj Ruam 5. Nrhiav cov molar feem ntawm qhov hnyav

Qhov kawg uas yuav tsum tau ua ua ntej daws qhov kev ua zauv yog txhawm rau txheeb tawm qhov feem ntawm cov molar ntawm peb cov kuab tshuaj. Nrhiav tus nqi no yog qhov yooj yim: tsuas yog hloov cov khoom siv rau hauv moles thiab tom qab ntawd pom qhov feem pua ntawm tag nrho cov naj npawb ntawm cov moles hauv cov khoom uas nyob hauv txhua qhov khoom. Hauv lwm lo lus, txhua qhov zauv feem sib npaug rau: (moles ntawm kev tivthaiv) / (tag nrho cov moles hauv cov khoom).

  • Cia peb hais peb daim ntawv qhia rau kev siv kua ntau 1 liter (l) dej thiab 1 liter (l) sucrose (qab zib). Hauv qhov no, peb yuav tsum nrhiav kom paub tus naj npawb ntawm cov moles sib xws rau txhua yam khoom. Txhawm rau ua qhov no, nws yog qhov tsim nyog los nrhiav qhov hnyav ntawm txhua tus ntawm lawv thiab tom qab ntawd siv lawv cov molar hnyav los hloov qhov txiaj ntsig no rau moles.

    • Qhov hnyav ntawm 1 l dej: 1,000 grams (g).
    • Qhov hnyav ntawm 1 l ntawm cov piam thaj ntau: kwv yees li 1,056, 7 g.
    • Cov kua dej: 1,000 g × 1 mol / 18, 015 g = 55. 51 moles.
    • Moles ntawm sucrose: 1056, 7 g × 1 mol / 342, 2965 g = 3.08 moles (nco ntsoov tias nws tuaj yeem tau txais cov piam thaj loj ntawm sucrose los ntawm nws cov tshuaj lom neeg, C12H22O11).
    • Tag nrho cov moles: 55, 51 + 3.08 = 58.59 moles
    • Molar feem ntawm dej: 55, 51 /58, 59 = 0, 947.
Xam Cov Vapor Siab Kauj Ruam 10
Xam Cov Vapor Siab Kauj Ruam 10

Kauj Ruam 6. Txhim kho qhov sib npaug

Thaum kawg, peb muaj txhua yam xav tau los daws Raoult's Law equation. Qhov no yog qhov yooj yim xav tsis thoob: tsuas yog nkag mus rau qhov muaj nuj nqis txheeb ze rau qhov hloov pauv hauv qhov sib npaug yooj yim thaum pib ntawm ntu: RAUkev daws teeb meem = Pebhnyav × xwmhnyav.

  • Hloov qhov txiaj ntsig tam sim no, peb muaj:

    • RAUkev daws teeb meem = (23.8 hli Hg) (0.947).
    • RAUkev daws teeb meem = 22, 54 hli Hg. Qhov no ua rau kev nkag siab - hauv cov ntsiab lus molar, tsuas muaj suab thaj me ntsis yaj hauv dej ntau (txawm hais tias, hauv cov lus siv tau, ob qho khoom xyaw muaj tib lub ntim), yog li cov pa siab yuav qis me ntsis.

Txoj Kev 3 ntawm 3: Nrhiav Vapor Siab hauv Cov Ntaub Ntawv Tshwj Xeeb

Xam Cov Vapor Siab Kauj Ruam 11
Xam Cov Vapor Siab Kauj Ruam 11

Kauj Ruam 1. Ceev faj txog Qhov Kub thiab Qhov Zoo Li Cas

Cov kws tshawb fawb feem ntau siv, kom yooj yim, "txheej txheem" teeb tsa qhov ntsuas kub thiab siab. Lawv raug hu ua Qhov Kub thiab Qhov Kub Zoo, lossis CNTP. Teeb meem cov pa nqus feem ntau xa mus rau CNTP cov xwm txheej, thiab nws yog qhov ua tau zoo kom muaj cov txiaj ntsig no ib txwm nco. CNTP qhov tseem ceeb tau txhais raws li:

  • Kub: 273, 15K / 0 ° C / 32 ° F.
  • Siab: 760 mm Hg / 1 atm / 101, 325 kPa.
Xam Cov Vapor Siab Kauj Ruam 12
Xam Cov Vapor Siab Kauj Ruam 12

Kauj Ruam 2. Rearrange Clausius-Clapeyron equation los nrhiav lwm yam kev hloov pauv

Hauv peb qhov piv txwv, hauv Ntu 1, peb tau pom tias Clausius-Clapeyron equation yog qhov muaj txiaj ntsig zoo rau kev txheeb xyuas cov pa ua pa rau cov tshuaj ntshiab. Txawm li cas los xij, tsis yog txhua lo lus nug yuav nug koj kom pom tus nqi P1 lossis P2 - ntau tus xav kom koj nrhiav tus nqi kub lossis txawm tias tus nqi ntawm ΔHvap ua. Hmoov zoo, hauv cov xwm txheej no, kom tau txais cov lus teb raug, nws txaus los rov ua qhov sib npaug kom nws tawm tsuas yog qhov sib txawv kom daws tau ntawm ib sab ntawm qhov sib npaug.

  • Piv txwv li, xav tias peb muaj cov kua tsis paub nrog lub zog ua pa sib npaug li 25 torr ntawm 273 K thiab 150 torr ntawm 325 K, thiab peb xav nrhiav lub enthalpy ntawm kev ua pa rau cov kua ntawd (ΔHvap ua). Peb tuaj yeem daws qhov teeb meem raws li hauv qab no:

    • ln (P1/P2) = (ΔHvap ua/R) ((1/T2) - (1/T1))
    • (ln (P1/P2))/((1/T2) - (1/T1)) = (ΔHvap ua/R)
    • R × (ln (P1/P2))/((1/T2) - (1/T1)) = ΔHvap ua
  • Tam sim no, peb nkag mus rau qhov tseem ceeb:

    • 8, 314 J/(K × Mol) × (-1, 79)/(-0, 00059) = ΔHvap ua
    • 8, 314 J/(K × Mol) × 3,033, 90 = ΔHvap ua = 25,223, 83 J/mol
Xeem Vapor Siab Kauj Ruam 13
Xeem Vapor Siab Kauj Ruam 13

Kauj Ruam 3. Coj mus rau hauv tus account qhov siab ntawm cov kuab tshuaj thaum nws tsim cov pa

Hauv peb qhov piv txwv ntawm Raoult txoj cai lij choj saum toj no, kev daws (suab thaj) tsis tsim cov pa ntawm nws tus kheej ntawm qhov kub ib txwm muaj (xav - thaum twg koj puas pom lub tais qab zib yaj ntawm lub rooj noj mov?). Txawm li cas los xij, thaum cov kuab tshuaj yaj tawm, nws yuav cuam tshuam nws cov pa siab. Peb yuav suav qhov no rau hauv tus as khauj thaum siv qhov hloov kho ntawm Raoult Txoj Cai kev ua lej: RAUkev daws teeb meem = Σ (P.tivthaiv × xwmtivthaiv). Sigma (Σ) txhais tau tias peb yuav tsum ntxiv txhua qhov kev sib zog ua pa ntawm cov khoom sib txawv kom tuaj txog ntawm cov lus teb.

  • Piv txwv li, cia peb hais tias koj muaj cov tshuaj ua los ntawm ob yam tshuaj: benzene thiab toluene. Tag nrho cov ntim ntawm cov tshuaj yog sib npaug 120 ml (ml): 60 ml ntawm benzene thiab 60 ml ntawm toluene. Qhov kub ntawm qhov kev daws teeb meem yog sib npaug rau 25 ° C, thiab cov pa ntawm txhua qhov ntawm cov tshuaj no, ntawm 25 ° C, yog sib npaug rau 95.1 mm Hg rau benzene thiab 28.4 mm Hg rau toluene. Muab cov txiaj ntsig no, tshawb xyuas qhov ua pa siab ntawm qhov kev daws teeb meem. Peb tuaj yeem daws cov lus nug raws li hauv qab no, siv tus txheej txheem qhov tseem ceeb ntawm qhov ntom ntom ntom ntom ntom ntom ntom ntom ntom, thiab cov pa nqus sib piv rau ob yam tshuaj:

    • Pawg (benzene): 60 ml = 0.060 l × 876, 5 kg / 1,000 l = 0.053 kg = 53g ua.
    • Pawg (toluene): 0.060 l × 866, 9 kg / 1,000 l = 0.052 kg = 52g ua.
    • Moles (benzene): 53 g × 1 mol / 78, 11 g = 0.679 mol.
    • Moles (toluene): 52 g × 1 mol / 92, 14 g = 0.564 mol.
    • Tag nrho cov moles: 0.679 + 0.564 = 1.243.
    • Molar feem (benzene): 0.679/1,243 = 0.546.
    • Molar feem (toluene): 0.564/1, 243 = 0.454.
  • Daws: P.kev daws teeb meem = Pebcov benzene × xwmcov benzene + P.cov toluene × xwmcov toluene.

    • RAUkev daws teeb meem = (95.1 mm Hg) (0.546) + (28.4 mm Hg) (0.454).
    • RAUkev daws teeb meem = 51.92 hli Hg + 12.89 hli Hg = 64, 81 hli Hg.

Lub tswv yim

  • Txhawm rau siv Clausius-Clapeyron sib npaug saum toj no, qhov ntsuas kub yuav tsum ntsuas hauv qib Kelvin (qhia hauv K). Yog tias koj muaj qhov kub nyob hauv degrees centigrade, koj yuav tsum hloov nws nrog cov qauv hauv qab no: TK 273 + TZSÇ.
  • Cov txheej txheem saum toj no ua haujlwm vim tias lub zog ncaj qha sib piv rau cov cua sov uas tau xa tawm. Qhov kub ntawm cov kua yog qhov ib puag ncig ib puag ncig uas ua pa siab nyob.

Pom zoo: