Molao oa Raoult ho Khemistri ke eng?
K'hemistri, haholo-holo thutong ea litharollo le litšobotsi tsa 'mele tsa metsoako, ho na le mohopolo oa bohlokoa o atisang ho sebelisoa ho hlalosa kamoo khatello ea mouoane ea ntho e fetohang kateng ha e kopantsoe le ntho e 'ngoe. Khopolo ena e tsejoa e le Molao oa Raoult. Molao ona ke motheo oa ho utloisisa liketsahalo tse fapaneng tsa letsatsi le letsatsi le lits'ebetso tsa indasteri, tse kang ho etsa litlolo tse nkhang hamonate, tlhoekiso ea joala, le melao-motheo ea ts'ebetso ea ho qhibilihisa. Sehlooho sena se tla tšohla tlhaloso ea Molao oa Raoult, mokhoa oa oona, mehlala ea ts'ebeliso ea oona, maemo ao o sebetsang tlas'a 'ona, le meeli ea oona.
Ho utloisisa Molao oa Raoult
Molao oa Raoult ke molao o bolelang hore khatello ea mouoane e sa fellang ea karolo e itseng tharollong e loketseng e lekana le karolo ea mole ea karolo eo tharollong. Molao ona o ile oa hlahisoa ka lekhetlo la pele ke setsebi sa k'hemistri sa Mofora, François-Marie Raoult, qetellong ea lekholo la bo19 la lilemo ha a ntse a ithuta litšobotsi tsa litharollo.
Ka mantsoe a bonolo, Molao oa Raoult o thusa ho araba potso ena: "Haeba motsoako o kopantsoe le ntho e 'ngoe, khatello ea mouoane ea motsoako o fetoha joang?" Karabo: khatello ea mouoane ea motsoako o tla fokotseha ho latela karolo ea motsoako o teng motsoakong.
Foromo ea Molao ea Raoult
Bakeng sa tharollo e nepahetseng e nang le likarolo tse peli (mohlala, A le B), Molao oa Raoult o ka ngoloa tjena:
\[
P_A = X_A \cdot P_A^0
\]
Lintlha:
– \( P_A \) = kgatello ya mouoane e sa fellang ya karolo ya A ka hara tharollo
– \( X_A \) = karoloana ea mole ea karolo ea A ka har'a tharollo
– \( P_A^0 \) = kgatello ya mouoane wa karolo e hlwekileng ya A (ka mocheso o tshwanang)
Haeba tharollong ho na le likarolo tse peli tse feto-fetohang (tse fetohang mouoane habonolo), joale khatello eohle ea mouoane ea tharollo e hlalosoa ka tsela ena:
\[
P_{kakaretso} = P_A + P_B = X_A \cdot P_A^0 + X_B \cdot P_B^0
\]
Ka hona, khatello eohle ea mouoane ea tharollo ke kakaretso ea khatello ea mouoane e sa fellang ea karolo ka 'ngoe.
Khopolo ea Karolo ea Mole Molaong oa Raoult
Karolo ea mole ke karolelano ea palo ea li-mole tsa karolo ho palo eohle ea li-mole tsa likarolo tsohle tse ka har'a tharollo. Foromo ke:
\[
X_A = \frac{n_A}{n_A + n_B}
\]
Lintlha:
– \( n_A \) = palo ea li-moles tsa karolo ea A
– \( n_B \) = palo ea li-moles tsa karolo ea B
Karolo ea mole e lula e na le boleng bo pakeng tsa 0 le 1. Haeba karolo ea mole ea karolo e le holimo, monehelo oa eona khatellong ea mouoane oa tharollo le oona o moholo.
Mohlala oa Palo ea Molao ea Raoult
Mohlala, tharollo e etsoa ka likarolo tsa A (solvent) le B (volatile solute). Hoa tsebahala hore:
– \( X_A = 0{,}7 \)
– \( P_A^0 = 100 \) mmHg
Ebe kgatello ya mouoane e sa fellang ya A ka hara tharollo ke:
\[
P_A = X_A \cdot P_A^0 = 0{,}7 \cdot 100 = 70 \text{ mmHg}
\]
Sena se bolela hore kgatello ya mouoane wa solvent A e theoha ho tloha ho 100 mmHg (ha e hlwekile) ho ya ho 70 mmHg kamora ho kopanya tharollo.
Haeba B le yona e feto-fetoha, mohlala \( X_B = 0{,}3 \) le \( P_B^0 = 50 \) mmHg:
\[
P_B = 0{,}3 \cdot 50 = 15 \text{ mmHg}
\]
Kahoo khatello eohle ea mouoane ea tharollo ke:
\[
P_{kakaretso} = 70 + 15 = 85 \mongolo{ mmHg}
\]
Kamano pakeng tsa Molao oa Raoult le Phokotso ea Khatello ea Mouoane
E 'ngoe ea lits'ebeliso tse tsebahalang haholo tsa Molao oa Raoult ke ho hlalosa phokotso ea khatello ea mouoane ha solute e sa fetoheng e eketsoa ho solute e feto-fetohang. Hobane solute e sa fetoheng ha e kenye letsoho khatellong ea mouoane, khatello ea mouoane ea tharollo e tlase ho feta ea solute e hloekileng.
Ha e le hantle, ha bokaholimo ba tharollo bo "tlala" ka dikarolwana tse qhibilihang, palo ya dimolek'hule tsa solvent tse ka phonyohang mohatong wa kgase e a fokotseha. Ka lebaka leo, kgatello ya mouwane e a fokotseha. Ketsahalo ena ke motheo wa thepa ya ho thulana ya ditharollo, tse kang:
– phokotso ea khatello ea mouoane
– bophahamo ba ntlha e belang
- ho tepella ha ntlha ea leqhoa
- khatello ea osmotic
Maemo a ho Sebelisa Molao oa Raoult (Tharollo e Loketseng)
Hase ditharollo tsohle tse latelang Molao wa Raoult ka ho phethahetseng. Molao ona o sebetsa hantle ho ditharollo tse loketseng, e leng ditharollo tse fihlelang maemo a latelang:
1. Matla a ho hohela pakeng tsa limolek'hule tse tšoanang le tse fapaneng a batla a tšoana.
Mohlala, matla a pakeng tsa A–A, B–B, le A–B a lekana ka ho lekana.
2. Ha ho na karabelo ea lik'hemik'hale e hlahang pakeng tsa likarolo tse ka har'a tharollo.
3. Ho kopanya ha ho bake liphetoho tse kholo molumong.
4. Mocheso o sa fetoheng (khatello ea mouoane e itšetlehile haholo ka mocheso, kahoo lipalo li etsoa mochesong o tšoanang).
Mehlala ea litharollo tse atamelang boikaketsi hangata ke metsoako ea lintho tse nang le meaho le lipolari tse tšoanang, mohlala, metsoako e meng ea li-hydrocarbon.
Ho kheloha Molaong oa Raoult
Ha e le hantle, ditharollo tse ngata tsa nnete di kheloha Molaong wa Raoult. Diphapang tsena di arotswe ka:
1. Ho kheloha ho hotle
Ho etsahala ha kgatello yohle ya mouoane ya tharollo e le kgolo ho feta kamoo ho boletsweng pele ke Molao wa Raoult. Sena se bolela hore dikamano pakeng tsa dimolek'hule tse fapaneng (A–B) di fokola ho feta tse pakeng tsa dimolek'hule tse tshwanang (A–A kapa B–B). Dimolek'hule di fetoha mouoane habonolo, di eketsa kgatello ya mouoane. Mohlala o tlwaelehileng: motswako wa ethanol le metsi metswakong e itseng o bontsha boitshwaro bona mme o ka etsa azeotrope.
2. Ho kheloha ho fosahetseng
E etsahala ha kgatello yohle ya mouoane e le ka tlase ho feta kamoo Molao wa Raoult o boletseng kateng. Sena se etsahala ha matla a kgahlang a A–B a le matla, kahoo dimolek'hule di "bolokwa" haholo mokgahlelong wa metsi mme ho ka etsahala hore di se ke tsa fetoha mouoane. Mohlala, motswako wa acetone le chloroform o bontsha ho kheloha ho fosahetseng ka lebaka la dikamano tse matla (mohlala, ditlamo tsa haeterojene).
Karolo ea Molao oa Raoult ho Distillation le Indastering
Molao oa Raoult o bohlokoa haholo ho raleng lits'ebetso tsa ho arola metsoako ea metsi, haholo-holo ho qhibilihisa. Ho qhibilihisa ho sebelisa liphapang tsa ho feto-fetoha ha likarolo. Ka ho utloisisa khatello ea mouoane e sa fellang ea karolo ka 'ngoe, bo-rasaense le baenjiniere ba ka bolela esale pele sebopeho sa mouoane o entsoeng ka holim'a tharollo.
Lisebelisoa tsa 'nete li kenyelletsa:
– tlhoekiso ea joala indastering ea lino le meriana
– ho sebetsoa ha peterole ka ho e qhalanya ka karoloana
– tlhahiso ea libano le lintho tse nkhang hamonate tse nang le motsoako oa lintho tse fetohang
– boenjiniere ba lik'hemik'hale lipalo tsa tekano ea mouoane le metsi
Meeli ea Molao oa Raoult
Leha Molao oa Raoult o le molemo haholo, o na le meeli e 'maloa, e leng:
– ha e nepahale bakeng sa ditharollo tse nang le dikamano tse matla (mohlala, ditharollo tsa electrolyte, ditharollo tse nang le dibonto tse matla tsa haeterojene)
– ha e loketse maemo a holimo haholo lits'ebetsong tse sa lokelang
– ha e khone ho hlalosa boitšoaro ba litharollo tse etsang azeotropes ntle le mehopolo e meng (mohlala, li-coefficient tsa ts'ebetso)
Maemong a mangata, bo-rasaense ba sebelisa litokiso tse kang li-coefficient tsa ts'ebetso (tharollong ea thermodynamics) ho etsa hore likhakanyo li nepahale haholoanyane.
Qetello
Molao oa Raoult ke molao-motheo oa motheo k'hemistri ea tharollo o bolelang hore khatello ea mouoane e sa fellang ea karolo e tharollong e loketseng e lekana ka ho toba le karolo ea eona ea mole. Molao ona o re lumella ho utloisisa ho theola khatello ea mouoane, ho bolela esale pele khatello eohle ea mouoane ea motsoako, le ho hlalosa mekhoa e fapaneng ea karohano e kang ho qhala. Leha ho le joalo, molao ona o loketse haholo bakeng sa litharollo tse loketseng 'me o ka khelosoa litharollong tsa 'nete ka likamano tse matla kapa tse rarahaneng tsa limolek'hule.
Haeba o ka rata, nka boela ka thusa ho theha mofuta o bonolo wa sengoloa bakeng sa baithuti ba sekolo se phahameng/se mahareng, kapa mofuta o tebileng haholoanyane o nang le puisano ya di-coefficient tsa mesebetsi le diagrama tsa mekhahlelo.
