Kodi Lamulo la Raoult mu Chemistry ndi chiyani?
Mu chemistry, makamaka pophunzira mayankho ndi mawonekedwe a zinthu zosakaniza, pali lingaliro lofunika lomwe nthawi zambiri limagwiritsidwa ntchito pofotokoza momwe mphamvu ya nthunzi ya chinthu imasinthira ikasakanizidwa ndi chinthu china. Lingaliroli limadziwika kuti Lamulo la Raoult. Lamuloli ndilo maziko omvetsetsa zochitika zosiyanasiyana za tsiku ndi tsiku ndi njira zamafakitale, monga kupanga mafuta onunkhira, kuyeretsa mowa, ndi mfundo zogwirira ntchito zoyeretsera. Nkhaniyi ikambirana tanthauzo la Lamulo la Raoult, njira yake, zitsanzo za momwe limagwiritsidwira ntchito, mikhalidwe yomwe limagwiritsidwa ntchito, ndi zoletsa zake.
Kumvetsetsa Chilamulo cha Raoult
Lamulo la Raoult ndi lamulo lomwe limanena kuti mphamvu ya nthunzi ya gawo linalake mu yankho labwino ndi yofanana ndi gawo la mole la gawo limenelo mu yankho. Lamuloli linaperekedwa koyamba ndi katswiri wa zamankhwala wa ku France, François-Marie Raoult, kumapeto kwa zaka za m'ma 19 pamene ankaphunzira za makhalidwe a mayankho.
Mwachidule, Lamulo la Raoult limathandiza kuyankha funso lakuti: "Ngati chosungunulira chisakanizidwa ndi chinthu china, kodi mphamvu ya nthunzi ya chosungunulira imasintha bwanji?" Yankho: mphamvu ya nthunzi ya chosungunulira idzachepa malinga ndi kuchuluka kwa chosungunulira chomwe chili mu chisakanizocho.
Fomula ya Malamulo ya Raoult
Kuti mupeze yankho labwino kwambiri lokhala ndi zigawo ziwiri (monga A ndi B), Lamulo la Raoult lingalembedwe motere:
\[
P_A = X_A \cdot P_A^0
\]
Zambiri:
– \( P_A \) = kupanikizika pang'ono kwa nthunzi ya gawo A mu yankho
– \( X_A \) = gawo la mole la gawo A mu yankho
– \( P_A^0 \) = kupanikizika kwa nthunzi ya gawo loyera A (pa kutentha komweko)
Ngati mu yankho muli zigawo ziwiri zomwe zonse zimakhala zosasinthasintha (zimasanduka mosavuta), ndiye kuti kuthamanga konse kwa nthunzi ya yankho kumafotokozedwa motere:
\[
P_{total} = P_A + P_B = X_A \cdot P_A^0 + X_B \cdot P_B^0
\]
Motero, kuthamanga konse kwa nthunzi ya yankho ndi kuchuluka kwa kuthamanga pang'ono kwa nthunzi ya gawo lililonse.
Lingaliro la Chigawo cha Mole mu Chilamulo cha Raoult
Gawo la mole ndi chiŵerengero cha chiwerengero cha ma mole a gawo ku chiwerengero chonse cha ma mole a zigawo zonse mu yankho. Fomula yake ndi iyi:
\[
X_A = \frac{n_A}{n_A + n_B}
\]
Zambiri:
– \( n_A \) = chiwerengero cha ma moles a gawo A
– \( n_B \) = chiwerengero cha ma moles a gawo B
Gawo la mole nthawi zonse limakhala ndi phindu pakati pa 0 ndi 1. Ngati gawo la mole la gawo lili lalikulu, gawo lake pa kuthamanga kwa nthunzi ya yankho nalonso ndi lalikulu.
Chitsanzo cha Kuwerengera Malamulo a Raoult
Mwachitsanzo, yankho limapangidwa kuchokera ku zigawo A (zosungunulira) ndi B (zosungunulira zosakhazikika). Zimadziwika kuti:
– \( X_A = 0{,}7 \)
– \( P_A^0 = 100 \) mmHg
Kenako mphamvu ya nthunzi ya A mu yankho ndi:
\[
P_A = X_A \cdot P_A^0 = 0{,}7 \cdot 100 = 70 \text{ mmHg}
\]
Izi zikutanthauza kuti mphamvu ya nthunzi ya solvent A imatsika kuchoka pa 100 mmHg (ikakhala yoyera) kufika pa 70 mmHg mutasakaniza mu yankho.
Ngati B nayonso ndi yosasinthasintha, mwachitsanzo \( X_B = 0{,}3 \) ndi \( P_B^0 = 50 \) mmHg:
\[
P_B = 0{,}3 \cdot 50 = 15 \text{ mmHg}
\]
Kotero mphamvu yonse ya nthunzi ya yankho ndi:
\[
P_{total} = 70 + 15 = 85 \text{ mmHg}
\]
Ubale Pakati pa Lamulo la Raoult ndi Kuchepa kwa Kupanikizika kwa Nthunzi
Chimodzi mwa ntchito zodziwika bwino za Raoult's Law ndikufotokozera kuchepa kwa mphamvu ya nthunzi pamene solute yosasinthasintha yawonjezeredwa ku solute yosasinthasintha. Chifukwa solute yosasinthasintha siyimathandizira ku mphamvu ya nthunzi, mphamvu ya nthunzi ya yankho ndi yotsika kuposa ya solute yoyera.
Mwachizolowezi, pamene pamwamba pa yankho "padzala" ndi tinthu tating'onoting'ono tomwe timasungunuka, chiwerengero cha mamolekyulu osungunulira omwe amatha kutuluka mu gawo la mpweya chimachepa. Zotsatira zake, kuthamanga kwa nthunzi kumachepa. Chochitika ichi ndicho maziko a makhalidwe ogwirizana a mayankho monga:
- kuchepa kwa kuthamanga kwa nthunzi
- wonjezani malo otentha
- kupsinjika kwa malo ozizira
- kuthamanga kwa osmotic
Mikhalidwe Yogwiritsira Ntchito Lamulo la Raoult (Yankho Labwino)
Si njira zonse zothetsera mavuto zomwe zimatsatira Lamulo la Raoult bwino. Lamuloli limagwira ntchito bwino kwambiri pa njira zabwino zothetsera mavuto, zomwe ndi njira zomwe zimakwaniritsa zofunikira izi:
1. Mphamvu ya kukopa pakati pa mamolekyu ofanana ndi osiyana ndi yofanana kwambiri.
Mwachitsanzo, mphamvu pakati pa A–A, B–B, ndi A–B ndi zofanana.
2. Palibe kusintha kwa mankhwala komwe kumachitika pakati pa zigawo zomwe zili mu yankho.
3. Kusakaniza sikubweretsa kusintha kwakukulu kwa voliyumu.
4. Kutentha kosalekeza (kuthamanga kwa nthunzi kumadalira kwambiri kutentha, kotero kuwerengera kumachitika pa kutentha komweko).
Zitsanzo za mayankho omwe amafikira ku malingaliro abwino nthawi zambiri amakhala osakaniza zinthu zomwe zili ndi kapangidwe kofanana ndi ma polarities, mwachitsanzo zosakaniza zina za ma hydrocarbon.
Kupatuka ku Chilamulo cha Raoult
Mwachidule, mayankho ambiri enieni amasiyana ndi lamulo la Raoult. Zopatuka izi zimagawidwa m'magulu awa:
1. Kupotoka Kwabwino
Zimachitika pamene mphamvu yonse ya nthunzi ya yankho ndi yayikulu kuposa momwe Raoult's Law inaneneratu. Izi zikutanthauza kuti kuyanjana pakati pa mamolekyu osiyanasiyana (A–B) ndi kofooka kuposa komwe kulipo pakati pa mamolekyu ofanana (A–A kapena B–B). Mamolekyu amasanduka nthunzi mosavuta, zomwe zimawonjezera mphamvu ya nthunzi. Chitsanzo chodziwika bwino: chisakanizo cha ethanol ndi madzi pazinthu zina chimasonyeza khalidweli ndipo chingapangitse azeotrope.
2. Kupatuka Koyipa
Zimachitika pamene mphamvu yonse ya nthunzi ili yochepa kuposa momwe Raoult's Law inaneneratu. Izi zimachitika pamene mphamvu zokopa za A–B zili zolimba, kotero mamolekyu "amasungidwa" kwambiri mu gawo lamadzimadzi ndipo samatha kusungunuka. Mwachitsanzo, chisakanizo cha acetone ndi chloroform chimasonyeza kupotoka koipa chifukwa cha kuyanjana kwamphamvu (monga, ma hydrogen bonds).
Udindo wa Lamulo la Raoult mu Distillation ndi Makampani
Lamulo la Raoult ndi lofunika kwambiri popanga njira zolekanitsira zosakaniza zamadzimadzi, makamaka kusungunuka. Kusungunuka kumagwiritsa ntchito kusiyana kwa kusasinthasintha kwa zigawo. Pomvetsetsa kupsinjika pang'ono kwa nthunzi ya gawo lililonse, asayansi ndi mainjiniya amatha kulosera kapangidwe ka nthunzi yopangidwa pamwamba pa yankho.
Ntchito zenizeni zikuphatikizapo:
- kuyeretsa mowa m'mafakitale a zakumwa ndi mankhwala
- kukonza mafuta kudzera mu distillation ya magawo
- kupanga mafuta onunkhira ndi zinthu zina zosakaniza ndi zinthu zosungunuka
- uinjiniya wa mankhwala pakuwerengera kwa nthunzi ndi madzi
Zofooka za Lamulo la Raoult
Ngakhale kuti ndi yothandiza kwambiri, lamulo la Raoult lili ndi zoletsa zingapo, zomwe ndi:
- si yolondola pa mayankho omwe ali ndi kuyanjana kwamphamvu (monga mayankho a electrolyte, mayankho omwe ali ndi ma hydrogen bond amphamvu)
- sikoyenera kugwiritsidwa ntchito kwambiri m'makina osayenerera
- sangathe kufotokoza momwe mayankho omwe amapanga azeotropes popanda mfundo zina zowonjezera zimakhalira (monga ma coefficients a zochita)
Nthawi zambiri, asayansi amagwiritsa ntchito zowongolera monga ma coefficients a zochita (mu yankho la thermodynamics) kuti apangitse maulosi kukhala olondola kwambiri.
Mapeto
Lamulo la Raoult ndi mfundo yofunikira kwambiri mu chemistry ya yankho yomwe imati kuthamanga kwa nthunzi pang'ono kwa gawo mu yankho labwino kumagwirizana mwachindunji ndi gawo lake la mole. Lamuloli limatithandiza kumvetsetsa kutsika kwa nthunzi, kulosera kuthamanga kwa nthunzi yonse ya chisakanizo, ndikufotokozera njira zosiyanasiyana zolekanitsira monga kusungunuka. Komabe, lamuloli ndiloyenera kwambiri pa mayankho abwino ndipo limatha kupatutsidwa kuchokera ku mayankho enieni okhala ndi kuyanjana kwamphamvu kapena kovuta kwa mamolekyu.
Ngati mukufuna, ndingathandizenso kupanga nkhani yosavuta kwa ophunzira a sekondale/a sekondale, kapena nkhani yozama kwambiri yokhala ndi zokambirana za ma coefficients a zochita ndi ma diagram a magawo.
