Mitemo yeThermochemical muFizikisi
Thermochemistry ibazi resainzi rinoongorora hukama huripo pakati pemakemikoro (kana shanduko dzemuviri muchinhu) nesimba rinoperekedza kupisa (kupisa). Mupfungwa yefizikisi, thermochemistry inoshanda sebhiriji rakakosha pakati pepfungwa dzesimba, kupisa, basa, uye shanduko mumamiriro ezvinhu. Kana chiitiko chikaitika, simba harimbo "onekwa" kana "kunyangarika" pasina kana chiratidzo. Simba rinongochinja chimiro: kubva kusimba remakemikari kuenda kukupisa, kana zvinopesana - kupisa kunotorwa kuti kutungamire shanduko dzemakemikari. Nheyo dzinotonga izvi dzakapfupikiswa mumitemo yethermochemistry, iyo inoumba hwaro hwekuverenga kupisa kwekuita, kushanda zvakanaka kwesimba, uye kunyange dhizaini yehurongwa hwemaindasitiri.
Pfungwa Dzekutanga: Masisitimu, Zvakatipoteredza, uye Kupisa Kwekuita
Kuti unzwisise mitemo yethermochemistry, chinhu chekutanga chaunofanira kunzwisisa itsanangudzo dzesystem nenzvimbo dzakakomberedza. Sisitimu chikamu chemuchadenga chatiri kudzidza—semuenzaniso, zvinhu zvinopindira mumudziyo. Nzvimbo dzakakomberedza zvese zviri kunze kwesisitimu. Kuchinjana kwesimba pakati pesisitimu nenzvimbo dzakaipoteredza kunowanzoitika muchimiro chekupisa.
Kupisa kwekuita kunowanzo ratidzwa sekuchinja kwe enthalpy, inomiririrwa ne ΔH. Enthalpy huwandu hwe thermodynamic hunomiririra "simba riri mukati" rehurongwa huri pa pressure inogara iripo, uye hunobatsira zvikuru nekuti maitiro mazhinji anoitika pa pressure yemhepo. Kazhinji:
– Kana sisitimu ikaburitsa kupisa kunzvimbo dzakapoteredza, reaction yacho inenge iri exothermic uye ΔH inenge isina kunaka (ΔH < 0). - Kana sisitimu ikatora kupisa kubva munzvimbo dzakapoteredza, reaction yacho inenge iri endothermic uye ΔH inenge yakanaka (ΔH > 0).
Muenzaniso wakapfava we exothermic reaction ndiko kupiswa kwemafuta, nepo muenzaniso we endothermic reaction iri maitiro e photosynthesis (anoda simba kubva kuzuva).
Mutemo weKuchengetedza Simba seNheyo yeThermochemistry
Kuseri kwemitemo yese yethermochemistry kune musimboti mukuru wefizikisi: Mutemo weKuchengetedza Simba, uyo unoumba musimboti weMutemo wekutanga weThermodynamics. Mutemo uyu unoti simba harigone kugadzirwa kana kuparadzwa, asi rinogona kungochinja chimiro. Mukunyora kwethermodynamic, shanduko yesimba remukati (ΔU) ine chekuita nekupisa (Q) nebasa (W) ne:
ΔU = Q − W
Chiratidzo netsananguro yebasa zvinogona kusiyana zvichienderana netsika, asi pfungwa huru yakafanana: kana sisitimu ikagamuchira kupisa, simba rayo remukati rinowanzowedzera; kana sisitimu ikashanda pane zvakaipoteredza, simba rayo remukati rinowanzoderera. Muzviitiko zvakawanda zve thermochemical—kunyanya kana paine kumanikidzwa kwakasimba—enthalpy (H) inowanzo shandiswa, saka kupisa kana paine kumanikidzwa kwakasimba kwakaenzana neΔH.
Nehwaro uhwu, thermochemistry inoona maitiro kwete sekuchinja kwezvinhu chete, asi sekuchinja kwesimba kunogona kuverengerwa nemazvo.
Mutemo waHess: Kupisa kweKupindura inzira yakazvimirira
Mumwe wemitemo inonyanya kukosha yethermochemistry ndiHess's Law. Mutemo uyu unoti kuchinja kwese kwe enthalpy kwe reaction kunoenderana chete nemamiriro ekutanga neekupedzisira, kwete panzira ye reaction. Izvi zvinoreva kuti kana reaction ikagona kuitika mumatanho akati wandei, huwandu hwekupisa (ΔH) hunogadzirwa kana kunyudzwa huchaenzana nekupisa kwe reaction yakananga, chero bedzi reactants nezvigadzirwa zvekupedzisira zvakafanana.
Pamasvomhu, kana mhinduro A → B inogona kupatsanurwa kuita:
– A → C (ΔH₁)
– C → B (ΔH₂)
saka:
ΔH huwandu = ΔH₁ + ΔH₂
Mutemo waHess unobatsira nekuti maitiro mazhinji akaoma kuyera kupisa kwawo zvakananga. Nekupatsanura maitiro kuita matanho anowanikwa data, tinogona kuverenga ΔH zvisina kunanga. Mufizikisi inoshandiswa uye yeindasitiri, mutemo uyu unobatsira kufanotaura zvinodiwa nesimba remakemikari, zvakaita sekugadzirwa kweammonia, kunatswa kwesimbi, uye kunyange maitiro ari mumabhatiri.
Mutemo waLavoisier–Laplace: Maitiro Ekudzoka Ane ΔH yeChiratidzo Chakapesana
Mumwe mutemo unokosha we thermochemical ndiLavoisier–Laplace Law, iyo inotaura kuti kupisa kwekuita kweimwe nzira kwakaenzana muhukuru asi zvinopesana muchiratidzo chekupisa kwe reverse reaction. Nemamwe mashoko:
Kana mhinduro yacho:
A → B ine ΔH = x,
wobva wadzokorora zvakare:
B → A ine ΔH = −x.
Pfungwa iyi inoita seiri nyore, asi inokosha. Inotaura kuti shanduko dzesimba dzinotevera symmetry yemamiriro ezvinhu: kana huwandu hwakati hwesimba hukaburitswa kubva kuA kuenda kuB, simba rakafanana rinofanira kutorwa kuti ridzoke kubva kuB kuenda kuA. Pfungwa iyi inoshandiswa mukuongorora matenderedzwa esimba, kusanganisira mainjini ekupisa, masisitimu efiriji, uye kuverenga simba remabhondi mukati memamorekuru.
Kuumbwa kweEnthalpy uye Kupiswa kweEnthalpy
Kuti zvive nyore kuverenga thermochemical, masayendisiti anotsanangura mhando dzakasiyana dze enthalpies:
1. Enthalpy yakajairika yekuumbwa (ΔHf°)
Uku ndiko kuchinja kwe enthalpy kana mole imwe yekombuta ichiumbwa kubva muzvinhu zvayo pasi pemamiriro akajairwa (kazhinji 1 atm ne25°C). Kukosha uku ndiko "chivakwa" pakuverenga ΔH ye reaction.
2. Enthalpy yakajairika yekupisa (ΔHc°)
Kuchinja kwe enthalpy kana mole imwe yechinhu yapiswa zvachose mu oxygen. Kupisa kunowanzova exothermic, saka ΔHc° inowanzova negative.
Ne enthalpy yedata rekuumbwa, shanduko ye enthalpy ye reaction inogona kuverengerwa kuburikidza ne:
ΔHreaction = Σ(ΔHf° chigadzirwa) − Σ(ΔHf° reactant)
Fomura iyi inowanzoshandiswa mu physical chemistry uye chemical physics, kunyanya pakudzidza maitiro pasi pemamiriro ezvinhu akafanana.
Calorimetry: Maitiro Ekuyera Kupisa Kwekuita
Mitemo yethermochemistry haisi yedzidziso chete asi inogonawo kuyedzwa nekuyedza. Nzira huru yekuyera kupisa kwekuita ndeye calorimetry, inova ndiyo yekuyera kuchinjana kwekupisa uchishandisa calorimeter.
Mukuedza kuri nyore kwe calorimetry, kupisa kunoburitswa kana kunyudzwa ne reaction kunochinja tembiricha yemvura yakapoteredza kana chimwe chinhu. Hukama hwakakosha ndehwekuti:
Q = mc ΔT
ne:
– Q = kupisa (Joules)
– m = huremu (kg kana g)
– c = kupisa kwakananga (J/kg·K kana J/g·°C)
– ΔT = kuchinja kwetembiricha
Mu calorimeter yebhomba, kuitika kwekupisa kunoitika mumudziyo wakavharwa, zvichichengetedza huwandu husingachinji. Izvi zvine chekuita nekuchinja kwesimba remukati (ΔU), asi zvinogona kushandurwa kuita ΔH kana zvichidikanwa.
Kukosha muFizikisi neHupenyu Hwechokwadi
Thermochemistry ine simba guru mufizikisi inoshandiswa. Mumunda wesimba, inobatsira kuona kukosha kwemakalori emafuta, izvo zvakakosha pakugadzira magetsi, mainjini emotokari, uye kuongorora mashandiro esimba. Musainzi yezvinhu, thermochemistry inotsanangura kuti nei mamwe maitiro mukugadzira simende, simbi, kana zviumbwa zvesimbi achida tembiricha yakakwira uye simba rakawanda. Mumunda wezvakatipoteredza, kuverenga kupisa kwekutsva kwakakosha pakuburitsa magasi egreenhouse uye nzira dzekuderedza kukanganiswa kwekudziya kwepasi rose.
Kunyangwe mune zvebhayoloji, thermochemistry inotsanangura kuti muviri unowana sei simba kubva muchikafu kuburikidza nemaitiro emetabolism ayo ari maitiro emakemikari anodzorwa zvakanyanya.
Penutup
Mitemo yethermochemistry mufizikisi inotaura kuti maitiro emakemikari uye shanduko dzemuviri zvinogara zvichibatanidzwa nekuchinja kwesimba kunoyerwa. Zvichibva pakuchengetedzwa kwesimba, mutemo waHess, uye mutemo waLavoisier-Laplace, tinogona kuverenga nekufanotaura kupisa kwekuita, zvese kuti tinzwisise zviitiko zvechisikigo uye kugadzira maitiro emaindasitiri. Thermochemistry haisi muunganidzwa wemafomula chete, asi maonero esainzi anoratidza kuti shanduko yega yega muzvinhu inogara iine "mutengo" wesimba kana "mubairo." Kunzwisisa mitemo iyi kunoreva kunzwisisa imwe yenheyo huru dzekudyidzana pakati pezvinhu nesimba muchadenga.
Kana muchida, ndinogona kuwedzera muenzaniso wekuverenga ΔH ndichishandisa Hess's Law kana ΔHf° data, ine matanho.
