chemical volcano

Ib qho ntawm cov tshuaj lom neeg zoo nkauj tshaj plaws yog cov txheej txheem decomposition ntawm ammonium dichromate (VI) (NH4) 2Cr2O7, hu ua "chemical volcano". Thaum lub sij hawm cov tshuaj tiv thaiv, ib tug loj npaum li cas ntawm ntxeem tau tshuaj yog tso tawm, lub hom phiaj ua raws li volcanic lava. Nyob rau hauv thaum ntxov hnub ntawm xinesmas, lub decomposition ntawm (NH4) 2Cr2O7 txawm siv raws li ib tug "tshuaj nyhuv"! Cov kws sim xav ua qhov kev sim no tau hais kom tsis txhob ua hauv tsev (vim qhov kev tso tawm ntawm cov plua plav ya tuaj yeem ua rau cov pa phem hauv tsev).

Txhawm rau ua qhov kev sim, koj yuav xav tau lub plooj (porcelain crucible) (lossis lwm yam khoom siv hluav taws xob) uas muaj ammonium (VI) dichromate (NH)₄)₂Cr₂O₇ (duab 1). Muab lub crucible tso rau saum lub mound ntawm xuab zeb simulating lub roob hluav taws kub (Pic 2) thiab teeb lub txiv kab ntxwv hmoov nrog ib tug match (Pic 3). Tom qab qee lub sijhawm, cov txheej txheem sai sai ntawm kev puas tsuaj ntawm cov khoom sib xyaw pib, ua rau tso tawm cov khoom siv roj ntau ntau, uas ua rau cov ntxeem tau chromium oxide (III) Cr.₂O₃ (Duab 4, 5 thiab 6). Tom qab qhov kawg ntawm cov tshuaj tiv thaiv, txhua yam nyob ib puag ncig yog npog nrog plua plav ntsuab tsaus (duab 7).

Cov tshuaj tiv thaiv tsis tu ncua ntawm ammonium dichromate (VI) tuaj yeem sau los ntawm qhov sib npaug:

Kev hloov pauv yog cov tshuaj tiv thaiv redox (lub npe hu ua redox cov tshuaj tiv thaiv), thaum lub sijhawm oxidation lub xeev ntawm cov atoms xaiv hloov. Hauv cov tshuaj tiv thaiv no, tus neeg sawv cev oxidizing (ib yam khoom uas tau txais electrons thiab txo nws cov oxidation xeev) yog chromium (VI):

Tus neeg sawv cev txo qis (ib yam khoom uas pub cov khoom siv hluav taws xob thiab, yog li ntawd, nce qib ntawm oxidation) yog nitrogen muaj nyob rau hauv ammonium ion (peb muab rau hauv tus account ob nitrogen atoms vim N.₂):

Txij li tus naj npawb ntawm cov khoom siv hluav taws xob pub dawb los ntawm tus neeg sawv cev txo qis yuav tsum sib npaug ntawm cov khoom siv hluav taws xob uas tau txais los ntawm tus neeg sawv cev oxidizing, peb muab thawj qhov sib npaug los ntawm 2 ntawm ob sab thiab sib npaug ntawm cov seem ntawm cov pa oxygen thiab hydrogen atoms.