Mutemo waRaoult muKemistri chii?
Mukemikari, kunyanya mukudzidza mhinduro uye hunhu hwemuviri hwemusanganiswa, pane pfungwa inokosha inowanzo shandiswa kutsanangura kuti kumanikidzwa kwemweya wechinhu kunochinja sei kana kusanganiswa nechimwe chinhu. Pfungwa iyi inozivikanwa seMutemo waRaoult. Mutemo uyu ndiwo hwaro hwekunzwisisa zviitiko zvakasiyana-siyana zvezuva nezuva uye maitiro emaindasitiri, zvakaita sekugadzira zvinonhuhwirira, kuchenesa doro, uye misimboti yekushanda kwe distillation. Chinyorwa chino chichakurukura tsananguro yeMutemo waRaoult, fomura yawo, mienzaniso yekushandiswa kwawo, mamiriro ayo unoshanda, uye zvipingamupinyi zvawo.
Kunzwisisa Mutemo waRaoult
Mutemo waRaoult mutemo unoti kumanikidzwa kwemweya wechikamu chechinhu chiri mumhinduro yakanaka kunoenderana nechikamu chemole chechikamu ichocho chiri mumhinduro. Mutemo uyu wakatanga kutaurwa nenyanzvi yemakemikari yekuFrance, François-Marie Raoult, mukupera kwezana remakore rechi19 panguva yaidzidza nezvehunhu hwemhinduro.
Muchidimbu, Mutemo waRaoult unobatsira kupindura mubvunzo uyu: "Kana chinhu chinonyungudutsa chikasanganiswa nechimwe chinhu, kumanikidzwa kwemhepo inonyungudutsa kunochinja sei?" Mhinduro: kumanikidzwa kwemhepo inonyungudutsa kuchaderera zvichienderana nehuwandu hwechinhu chinonyungudutsa chiri mumusanganiswa.
Fomura yeMutemo waRaoult
Kuti pave nemhinduro yakanaka ine zvikamu zviviri (semuenzaniso A naB), Mutemo waRaoult unogona kunyorwa seizvi:
\[
P_A = X_A \cdot P_A^0
\]
Information:
– \( P_A \) = kumanikidzwa kweutsi hwechikamu A mumushonga
– \( X_A \) = chikamu chemole chechikamu A mumhinduro
– \( P_A^0 \) = kumanikidzwa kweutsi hwechikamu chakachena A (patembiricha yakafanana)
Kana mumhinduro muine zvinhu zviviri zvinoshanduka-shanduka (zvinopera nyore nyore), saka kumanikidzwa kwemhepo yese yemhinduro kunoratidzwa seizvi:
\[
P_{total} = P_A + P_B = X_A \cdot P_A^0 + X_B \cdot P_B^0
\]
Saka, kumanikidzwa kwese kwemupfudze wemushonga ndiko huwandu hwekushomeka kwemupfudze wechikamu chimwe nechimwe.
Pfungwa yeChikamu cheMole muMutemo waRaoult
Chikamu cheMole ndicho chiyero chehuwandu hwemamole echikamu chimwe nechimwe kusvika kuhuwandu hwemamole ezvikamu zvese zviri mumushonga. Fomura yacho ndeiyi:
\[
X_A = \frac{n_A}{n_A + n_B}
\]
Information:
– \( n_A \) = nhamba yemamoles echikamu A
– \( n_B \) = nhamba yemamoles echikamu B
Chikamu chemole chinogara chiri pakati pe0 ne1. Kana chikamu chemole chechikamu chakakwira, mupiro wacho mukumanikidzwa kwemhepo yemushonga wacho wakakurawo.
Muenzaniso weKuverengwa kweMutemo waRaoult
Semuenzaniso, mhinduro inogadzirwa kubva muzvikamu A (solvent) uye B (volatile solute). Zvinozivikanwa kuti:
– \( X_A = 0{,}7 \)
– \( P_A^0 = 100 \) mmHg
Zvadaro chikamu chekumanikidzwa kwemvura cheA mumushonga ndeichi:
\[
P_A = X_A \cdot P_A^0 = 0{,}7 \cdot 100 = 70 \text{ mmHg}
\]
Izvi zvinoreva kuti kumanikidzwa kwemhepo inonyungudutsa A kunoderera kubva pa100 mmHg (kana yakachena) kusvika pa70 mmHg mushure mekusanganisa mvura.
Kana B ichichinja-chinjawo, semuenzaniso \( X_B = 0{,}3 \) uye \( P_B^0 = 50 \) mmHg:
\[
P_B = 0{,}3 \cdot 50 = 15 \text{ mmHg}
\]
Saka kumanikidzwa kwese kwemupfu wemhinduro ndekwekuti:
\[
P_{total} = 70 + 15 = 85 \text{ mmHg}
\]
Hukama huripo pakati peMutemo waRaoult neKuderera kweKumanikidzwa kweVapor
Imwe yenzira dzakakurumbira dzekushandisa Mutemo waRaoult ndeyekutsanangura kudzikira kwekumanikidzwa kwemhepo kana chinhu chisina kugadzikana chikaiswa muchinhu chinonyunguduka. Nekuti chinhu chisina kugadzikana hachibatsiri pakumanikidzwa kwemhepo, kumanikidzwa kwemhepo kwemushonga kwakaderera pane kwechinhu chisina kuchena.
Mukuita, kana pamusoro pemushonga "pakazara" nezvidimbu zvinonyunguduka, huwandu hwemamorekuru anonyunguduka anogona kubuda muchikamu chegasi hunoderera. Nekuda kweizvozvo, kumanikidzwa kwemhepo kunoderera. Ichi chiitiko ndicho hwaro hwehunhu hwekugadzirisa kwemhinduro, dzakadai se:
- kudzikira kwekumanikidzwa kwemhepo
- kukwidziridzwa kwenzvimbo yekufashaira
- kuora mwoyo kwenzvimbo yechando
- kumanikidzwa kwe osmotic
Mamiriro Ekushandisa Mutemo waRaoult (Mhinduro Yakanaka)
Hadzisi dzese mhinduro dzinotevedzera Mutemo waRaoult zvakakwana. Mutemo uyu unoshanda zvakanyanya kune mhinduro dzakakodzera, kureva mhinduro dzinosangana nemamiriro anotevera:
1. Simba rekukwezvana pakati pemamorekuru akafanana neakasiyana rakafanana.
Semuenzaniso, masimba ari pakati peA–A, B–B, naA–B akaenzana.
2. Hapana makemikari anoitika pakati pezvinhu zviri mumushonga.
3. Kusanganisa hakukonzeri shanduko huru muhuwandu.
4. Kupisa nguva dzose (kumanikidzwa kwemhepo kunoenderana zvikuru nekupisa, saka kuverenga kunoitwa pakupisa kwakafanana).
Mienzaniso yemhinduro dzinoenderana nepfungwa dzakanaka dzinowanzo kuve musanganiswa wezvinhu zvine maumbirwo akafanana uye polarities, semuenzaniso mimwe misanganiswa yemahydrocarbon.
Kutsauka kubva kuMutemo waRaoult
Muchokwadi, mhinduro dzakawanda dzechokwadi dzinosiyana neMutemo waRaoult. Kutsauka uku kwakakamurwa kuita:
1. Kutsauka Kwakanaka
Zvinoitika kana kumanikidzwa kwemhepo kwese kwemushonga kwakakura kupfuura kwakafanotaurwa neMutemo waRaoult. Izvi zvinoreva kuti kudyidzana pakati pemamorekuru akasiyana (A–B) hakuna kusimba pane kuri pakati pemamorekuru akafanana (A–A kana B–B). Mamorekuru anopwanyika zviri nyore, zvichiwedzera kumanikidzwa kwemhepo. Muenzaniso wakajairika: musanganiswa weethanol nemvura pane zvimwe zvinhu zvinoratidza maitiro aya uye unogona kuumba azeotrope.
2. Kutsauka Kwakaipa
Zvinoitika kana kumanikidzwa kwemhepo yose kwakaderera pane zvakafanotaurwa neMutemo waRaoult. Izvi zvinoitika kana masimba anokwezva eA–B akasimba, saka mamorekuru "anochengetwa" zvakanyanya muchikamu chemvura uye haawanzo pwanyika. Semuenzaniso, musanganiswa weacetone nechloroform unoratidza kutsauka kwakashata nekuda kwekubatana kwakasimba (semuenzaniso, hydrogen bonds).
Basa reMutemo waRaoult muDistillation neIndasitiri
Mutemo waRaoult wakakosha pakugadzira maitiro ekuparadzanisa musanganiswa wemvura, kunyanya kudistilla. Kudistilla kunoshandisa mutsauko mukushanduka-shanduka kwezvikamu. Nekunzwisisa kumanikidzwa kweutsi hwechikamu chimwe nechimwe, masayendisiti nemainjiniya vanogona kufanotaura kuumbwa kweutsi hwakagadzirwa pamusoro pemhinduro.
Mashandisirwo chaiwo anosanganisira:
- kucheneswa kwedoro mumaindasitiri ezvinwiwa nemishonga
- kugadziriswa kwepeturu kuburikidza nekudiridza zvikamu
- kugadzirwa kwezvinonhuwira nezvinhu zvinosanganisa musanganiswa wezvinhu zvinoputika
- hunyanzvi hwemakemikari mukuverenga kwehuwandu hwemvura-mvura
Miganhu yeMutemo waRaoult
Kunyange zvazvo zvichibatsira zvikuru, Mutemo waRaoult une zvipingamupinyi zvakawanda, zvinoti:
- hazvina kururama pamhinduro dzine hukama hwakasimba (semuenzaniso mhinduro dze electrolyte, mhinduro dzine hydrogen bonds inotonga)
- hazvina kukodzera kushandiswa zvakanyanya muzvinhu zvisina kunaka
- haikwanise kutsanangura maitiro emhinduro dzinogadzira azeotropes dzisina mamwe mazano (semuenzaniso, ma coefficients ebasa)
Kazhinji, masayendisiti anoshandisa magadzirisirwo akadai se activity coefficients (mu solution thermodynamics) kuti fungidziro dzive dzakarurama.
Mhedziso
Mutemo waRaoult ipfungwa huru mukemikari yemhinduro inotaura kuti kumanikidzwa kweutsi hwechikamu chechinhu chiri mumhinduro yakanaka kunoenderana zvakananga nechikamu chayo chemole. Mutemo uyu unotibvumira kunzwisisa kudzikiswa kweutsi hweutsi, kufanotaura huwandu hweutsi hwemusanganiswa, uye kutsanangura maitiro akasiyana-siyana ekuparadzanisa akadai sekunyungudutsa. Zvisinei, mutemo uyu wakakodzera mhinduro dzakanaka uye unogona kutsauswa kubva mumhinduro chaidzo dzine hukama hwakasimba kana hwakaoma hwemamorekuru.
Kana muchida, ndinogonawo kubatsira kugadzira chinyorwa chiri nyore chevadzidzi vechikoro chesekondari/chesekondari, kana chinyorwa chakadzama chine hurukuro yemabasa nemadhayagiramu echikamu.
