Dissociation ntawm lub ntsev, kua qaub thiab alkalis. Kev tshawb xav thiab ua daim ntawv thov

Rau lub cev Science News for KIDS thiab Biochemistry raug zuag qhia tag nrho cov txheej txheem nyob rau hauv uas particulate teeb meem - molecules, ions (zoo them hais hu ua cations thiab tsis zoo them hais, hu ua anions) radicals tawg ua me me mus rau hauv me me hais. Qhov no yog hu ua dissociation, uas yog Latin rau "dissociation" txhais tau tias "kev sib cais." Nws yog yus muaj los ntawm tej kev qhia raws li cov "degree ntawm dissociation", uas qhia tus piv ntawm dissociated hais rau tag nrho cov xov tooj ntawm hais ua ntej lub cev qhuav dej, piv txwv li, lub feem ntawm hais tias yog disintegrated. Tus txheej txheem ntawm disintegration ntawm tus hais tej zaum yuav tshwm sim raws li ib tug tshwm sim ntawm tej yam nyob rau hauv lub tshuaj, qhov xwm ntawm cov teebmeem txiav txim hom dissociation. Paub qhov txawv thermal dissociation, photodissociation, dissociation nyob rau hauv tus ntawm ionizing tawg, electrolytic dissociation. Dissociation yog qhov fab ntxeev ntawm lub koom haum thiab recombination. Qhov no tus txheej txheem no feem ntau tsis meej pem nrog ionization.

Electrolytic dissociation yog ib hom ntawm dissociation, tshwm sim nyob rau hauv tus ntawm kuab molecules thiab polar bears tshuaj cim. Tshuaj uas muaj peev xwm dissociate nyob rau hauv ib tug hnyav rau hauv ions thiab kev hluav taws xob tam sim no, hu ua ntsha (acid, ntsev, puag). Tshuaj uas thaum yaj tsis dissociate rau hauv ions (alcohols, esters, carbohydrates, etc.) yog tsis electrolytes. Qhov tseem ceeb tshaj electrolytes Hnyav - dej. Dej nws tus kheej yog yus raws li ib tug tsis muaj zog ntsha. Ncov qaumteb qabteb kuab tshuaj (e.g., ethanol, ammonia thiab acetic acid) no kuj muaj peev xwm ntawm dissolving lub electrolytes. Dissociation ntawm acids, alkalis, zoo li lub dissociation ntawm ntsev tshwm sim nyob rau hauv aqueous daws teeb meem. Cov ntsev ntawm - qhov no hauv chav kawm ntawv ntawm cov tshuaj lub tebchaw uas nws molecules yog muaj li ntawm zoo them hais (hlau cations), thiab tsis zoo them hais (acid anion residue). Acid tas li ntawd ntsev, tsis zoo li cov pa ntsev muaj ob hom ntawm cations (hlau thiab hydrogen) thiab ib tug acid anion residue. Thaum yaj nyob rau hauv dej lwg me me decompose nyob rau hauv lub ntsev ions. Cov ntsev muaj peev xwm yuav zoo tu qab tso qhuav dej.

Paub qhov txawv ntawm muaj zog thiab tsis muaj zog electrolytes. Nyob rau hauv lub classical kev tshawb xav ntawm electrolytic dissociation txheej txheem pom tau hais tias pom tau hais tias reversible, tab sis qhov no daim ntawv qhia tsuas yog siv rau tsis muaj zog electrolytes nyob rau hauv nta kev daws teeb meem. Ib electrolytic dissociation ntawm acids, bases, ntsev, yog ib tug irreversible txheej txheem, txij li thaum ntsev (zoo tag nrho tsuas yog tej yam complex), acids thiab bases (cov neeg tsim nrog alkali thiab alkaline ntiaj teb co) yog muaj zog electrolytes thiab molecules nyob rau hauv tsis muaj zog daws teeb meem kiag li (100 %) dissociated rau hauv ions. Muaj zog electrolytes: NaCl (sodium tshuaj dawb), HNO3 (nitric acid), HClO3 (chloric acid), CaCl2 (calcium chloride), NaOH (sodium hydroxide). Tsis muaj zog electrolytes: NH4OH (ammonium hydroxide), H2CO3 (carbonic acid), CH3COOH (acetic acid) thiab feem ntau ntawm cov organic acids thiab bases. Lawv thaum yaj nyob rau hauv dej yuav dissociate cov (feem ntau, qhov no tus nqi yog hom twg los ntawm 1 mus rau 10%).

Yog li ntawd, lub assertion hais tias kev daws ntawm ib tug muaj zog ntsha muaj tsuas ions, thiab nyob rau hauv ib tug tov ntawm tsis muaj zog electrolytes, mas nondecomposed molecules ntawm qhov teeb meem. Dissociation ntawm lub ntsev ua rau lub fact tias nyob rau hauv cov tshuaj muaj tsuas hlau ion thiab ib tug acid residue (e.g., sodium Na + ntawv thiab tshuaj anion Cl-) thiab nondecomposed molecules (NaCl) muaj ntsev. Dissociation acid ntsev ua rau yus lub tsim nyob rau hauv cov tshuaj ntawm ib tug hlau ntawv, hydrogen ntawv thiab cov acid anion residue. Piv txwv li, acid ntsev NaHCO3 (sodium bicarbonate) dissociates rau hauv ib lub sodium ntawv (Na +), hydrogen ntawv (H) thiab ib tug anion ntawm carbonic acid acid residue (SO3-).

Yog hais tias cov tshuaj (melt) muab tso nyob rau hauv lub electrolytic cell ntsha (txog ntsha nrog anode thiab cathode), thaum voltage yog thov mus pib lub directional zog ntawm them hais mus rau lub electrodes ntawm opposite xwb: zoo cations - mus rau lub npe phem rau them cathode, thaum tsis zoo anions - mus rau lub zoo them anode. Qhov no cov khoom teejtug uas electrolytes, nyob rau hauv particular, dissociation ntsev kheev siv nyob rau hauv cov kos duab. electrolysis yog nqa tawm muaj zus tau tej cov txhuas, tooj liab (los ntawm electrolytic refining). Electrolysis ua lub purest tshuaj xws purity tsis tau los ntawm lwm txoj kev (distillation, crystallization, thiab lwm tus). Nrog electrolysis co rho tawm los ntawm ores, ntxuav, txij thaum lub cathode yog tso xwb nyob rau lub hlau ntawv thiab cov impurities nyob twj ywm nyob rau hauv cov tshuaj los yog yaj. Cov tshwm sim ntawm dissociation ntawm ntsev underlies ua ntshiab hydrogen thiab ntshiab chlorine. Nyob rau hauv dej, sodium tshuaj dawb yog decomposed rau hauv ions: sodium ntawv thiab tshuaj anion. Thaum lub anode yuav muab sau ua ke ntshiab tshuaj nyob rau cathode - lub byproduct hydrogen, thiab cov tshuaj yuav tsim lwm tseem ceeb byproduct - sodium hydroxide.