Cov tshuaj electrolyte yog cov kua tshwj xeeb uas yog ib feem lossis tag nrho hauv daim ntawv them nqi (ions). Cov txheej txheem ntawm kev faib cov molecules rau hauv qhov tsis zoo (anions) thiab qhov zoo (cations) hais yog hu ua electrolytic dissociation. Dissociation nyob rau hauv cov kev daws teeb meem tsuas yog vim muaj peev xwm ntawm ions los cuam tshuam nrog cov molecules ntawm cov polar kua, uas ua raws li ib tug hnyav.
Dab tsi yog electrolytes
Electrolyte daws tau muab faib ua aqueous thiab non-aqueous. Cov dej tau kawm tau zoo heev thiab nthuav dav heev. Lawv pom muaj nyob rau hauv yuav luag txhua yam kabmob uas muaj sia nyob thiab koom nrog ntau yam tseem ceeb hauv cov txheej txheem lom neeg. Non-aqueous electrolytes yog siv los ua cov txheej txheem electrochemical thiab ntau yam tshuaj lom neeg. Lawv siv tau coj mus rau kev tsim cov khoom siv hluav taws xob tshiab. Lawv ua lub luag haujlwm tseem ceeb hauv cov cell photoelectrochemical, organic synthesis, electrolytic capacitors.
Electrolyte cov kev daws teeb meem nyob ntawm qib ntawm kev sib cais tuaj yeem muab faib uamuaj zog, nruab nrab thiab tsis muaj zog. Lub degree ntawm dissociation (α) yog qhov piv ntawm tus naj npawb ntawm cov molecules decomposed rau hauv nqi hais rau tag nrho cov molecules. Rau cov electrolytes muaj zog, tus nqi ntawm α mus txog 1, rau nruab nrab electrolytes α≈0.3, thiab rau cov electrolytes tsis muaj zog α<0, 1.
Muaj zog electrolytes feem ntau suav nrog cov ntsev, qee cov kua qaub - HCl, HBr, HI, HNO3, H2SO 4, HClO4, hydroxides ntawm barium, strontium, calcium thiab alkali hlau. Lwm cov hauv paus thiab cov kua qaub yog nruab nrab lossis tsis muaj zog electrolytes.
Cov khoom ntawm cov tshuaj electrolyte
Kev tsim cov kev daws teeb meem feem ntau nrog cov teebmeem thermal thiab ntim hloov pauv. Cov txheej txheem ntawm dissolving cov electrolyte nyob rau hauv cov kua yuav tshwm sim nyob rau hauv peb theem:
- Kev puas tsuaj ntawm cov khoom sib txuas thiab tshuaj lom neeg ntawm cov yaj electrolyte yuav tsum tau siv nyiaj ntau ntawm lub zog thiab yog li ntawd cov cua sov yog absorbed (∆Нdaws > 0).
- Nyob rau theem no, cov kuab tshuaj pib cuam tshuam nrog electrolyte ions, ua rau tsim cov solvates (hauv cov tshuaj aqueous - hydrates). Cov txheej txheem no yog hu ua kev daws teeb meem thiab yog exothermic, i.e. cua sov tso tawm (∆ Н hydr < 0).
- kauj ruam kawg yog kev nthuav dav. Qhov no yog ib qho kev faib tawm ntawm hydrates (solvates) nyob rau hauv lub ntim ntawm cov tshuaj. Cov txheej txheem no yuav tsum tau them nqi hluav taws xob thiab yog li qhov kev daws teeb meem txias (∆Нdif > 0).
Yog li, tag nrho cov thermal nyhuv ntawm electrolyte dissolution tuaj yeem sau tau raws li hauv qab no:
∆Нsolv=∆Нrelease + ∆Нhydr + ∆Н diff
Qhov kawg kos npe ntawm tag nrho cov thermal nyhuv ntawm electrolyte dissolution nyob ntawm seb cov khoom siv hluav taws xob cuam tshuam li cas. Cov txheej txheem no feem ntau yog endothermic.
Cov khoom ntawm kev daws yog nyob ntawm qhov xwm txheej ntawm nws cov khoom siv. Tsis tas li ntawd, cov khoom ntawm electrolyte raug cuam tshuam los ntawm kev sib xyaw ntawm cov tshuaj, siab thiab kub.
Raws li cov ntsiab lus ntawm cov tshuaj yaj, tag nrho cov tshuaj electrolyte tuaj yeem muab faib ua qhov tsis tshua muaj zog (uas muaj tsuas yog "cov kab" ntawm cov electrolyte), dilute (nrog cov ntsiab lus me me ntawm cov tshuaj yaj) thiab concentrated (nrog rau cov ntsiab lus tseem ceeb ntawm cov electrolyte).
Cov tshuaj tiv thaiv hauv cov tshuaj electrolyte, uas yog tshwm sim los ntawm kev hla ntawm cov hluav taws xob tam sim no, ua rau tso tawm qee yam ntawm cov electrodes. Qhov tshwm sim no yog hu ua electrolysis thiab feem ntau siv hauv kev lag luam niaj hnub. Hauv particular, electrolysis tsim txhuas, hydrogen, chlorine, sodium hydroxide, hydrogen peroxide thiab ntau lwm yam tseem ceeb.
