Redox tshua

Lo lus "oxidation" yog Ameslikas meant ib lub tshuaj sis raug zoo nrog cov pa mus tsim ib qho oxide, ua pa tau dabneeg raug lees paub tias raws li cov thawj oxidant. Los ntawm oxidizing to taub oxygen kev twb kev txuas, thiab nyob rau hauv restoration - rov qab nws. Yog li ntawd lub sij hawm "oxidation - restoration" tau ntev ua Science News for KIDS. Redox tshua tuaj tom qab yuav pom tau tias los ntawm xws li dab raws li ib tug tshwm sim ntawm uas muaj ib tug hloov lwm lub tsev ntawm electrons los ntawm ib tug atom mus rau lwm lub, yog li no lub sij hawm tau nrhiav ib tug nrug lub ntsiab lus. Piv txwv li, thaum magnesium combustion nyob rau hauv cov pa: 2Mg + O2 → 2MgO electron hloov tshwm sim los ntawm magnesium rau oxygen.

Redox tshua yog yus nyob rau hauv hais tias lawv sib tham nrog reagents paub oxidants thiab reductants. Tshuaj atoms uas pub electrons xam tau tias yog txo cov neeg ua hauj. Cov tshuaj tebchaw uas nws atoms coj electrons hu ua oxidants. Qhov saum toj no cov tshuaj tiv thaiv yog ib tug magnesium txo neeg sawv cev ntawm nws tus kheej yog oxidized, i.e. xa ib tug electron. Pa yog txo - yuav siv sij hawm ib tug electron thiab ib tug oxidizer. Lwm cov piv txwv: CuO + H2 → Cu + H2O. Thaum rhuab, cov tooj liab oxide nyob rau hauv ib tug hydrogen kwj tooj liab ions txais electrons los ntawm hydrogen. Raws li ib tug oxidizing neeg sawv cev, lawv yog txo kom elemental tooj liab. Hydrogen atoms pub electrons, raws li ib tug txo neeg sawv cev ntawm nws tus kheej yog oxidized thiab hydrogen.

Yog li, lub oxidation thiab yuav txo tau dab coj qhov chaw ib txhij: oxidized txo thiab oxidizing ua hauj lawm yog txo. Redox tshua thiaj li hu ua vim hais tias muaj yog ib tug inextricable txuas ntawm reciprocal dab. Uas yog, yog tias muaj atoms uas pub electrons, uas yog ib txwm tam sim no thiab xws li hais tias cov electrons noj. Nyob rau tib lub sij hawm li hais tias ntawm lub oxidizer thiab ib tug txo neeg sawv cev nyob rau hauv hloov cov neeg kawm ntawv ntawm oxidation. Raws li ib tug tshwm sim ntawm cov tshuaj tebchaw peev xwm yuav tsim muaj txhua yam ntawm atoms nyob rau hauv molecules.

Lub ntsiab yam ntawm redox tshua:

1. Intermolecular - oxidizable thiab reducible atoms muaj nyob rau hauv lub lwg me me ntawm txawv tshuaj, piv txwv li: 2HCl + ZN → ZnCl2 + H2 ↑ (zinc - reductant hydrogen ntawv - oxidant).
2. Intramolecular - oxidizable thiab reducible atoms muaj nyob rau hauv lub lwg me me ntawm ib yam tshuaj yeeb tshuaj, piv txwv li: KClO3 → 2KCl + 3O2 ↑ (nyob rau hauv ib tug qauv ntawm poov tshuaj chlorate oxygen - reductant chloro - oxidant).
3. Autoxidation-self-kho los yog disproportionation - ib yam tshuaj uas caij nyob rau hauv cov tshuaj tiv thaiv yog tus txo neeg saib xyuas thiab oxidizing neeg sawv cev, piv txwv li: 3HNO2 → HNO3 + 2NO ↑ + H2O ( ib tug nitrogen atom ntawm cov pa roj nitrous acid yog ob qho tib si ib tug txo neeg saib xyuas thiab oxidizing neeg sawv cev, cov oxidation khoom - ib tug nitric acid, txo khoom - nitrogen monoxide).
4. Comproportionation reproportsionirovanie los yog - ib tug thiab tib lub caij muaj ib tug txawv degree ntawm oxidation ntawm lub molecule, uas ua rau ib tug tib oxidation lub xeev, piv txwv li: NH4NO3 → N2O + 2H2O.

Redox tshua yog nyob rau hauv ib tug general daim ntawv los yog hluav taws xob. Ib tug yuav xav txog cov piv txwv ntawm cov tshuaj sis: 2FeCl3 + H2S → FeCl2 + S + 2HCl. Ntawm no, cov hlau atom yog ib qho oxidizing neeg sawv cev, vim hais tias nws yuav siv sij hawm ib tug electron thiab hloov nrog lub degree ntawm oxidation ntawm +3 rau +2: Fe + ³ + e → Fe + ². Ion leej faj kom txhob muaj neeg sawv cev yog oxidized, electrons thiab xa nws hloov oxidation lub xeev nyob -2 0: Sˉ² - e → S °. electron los yog ion-electron tshuav nyiaj li cas txoj kev yog siv rau cov kawm tuab si lug ntawm lub stoichiometric coefficients nyob rau hauv kab zauv.

Redox fab ntau thiab kuj zoo kawg thiab tseem ceeb, txij li thaum lawv yam underlie cov combustion kev ntawm lwj lwj, kev ua pa, metabolism, assimilation ntawm cov pa roj carbon dioxide nroj tsuag, raws li zoo raws li nyob rau lwm yam lom dab. Tsis tas li ntawd, lawv yog siv nyob rau hauv ntau yam industries rau cov co thiab uas tsis yog-hlau los ntawm lawv cov tebchaw. Piv txwv li, cov no yog raws li nyob rau hauv qhov kev npaj ntawm ammonia, sulfuric thiab nitric acids, ib co tsev ntaub ntawv, cov tshuaj thiab ntau lwm yam tseem ceeb cov khoom. Lawv kuj siv nyob rau hauv analytical Science News for KIDS rau kev txiav txim ntau yam tshuaj sib txuas.