Igerageza ry’icupa ry’ubururu: ubutabire, uburyo bwo kurikora, n’ibyo kwitegereza

Icupa ribonerana riri ku meza ya laboratwari. Risa n’aho ririmo amazi. Umuntu ararinyeganyeza, amazi arimo agahinduka ubururu bukeye cyane. Iyo rirambitswe hasi, ubwo bururu burashira mu munota umwe cyangwa ibiri. Ongera urinyeganyeze, ubururu buragaruka. Ibyuzuye rimwe bishobora gusubiramo ibi inshuro makumyabiri cyangwa zirenga.

Akenshi abanyeshuri bakeka ko hari ikintu cyari cyihishe mu icupa, cyangwa ko kunyeganyeza byavanze ibice bibiri by’amazi. Ibyo bitekerezo byombi biribeshya mu buryo bufasha kwiga. Ibara rituruka ku irangi rimwe gusa, methylene blue, riri hose mu mazi. Igihinduka ni umubare wa electron iryo rangi ritwaye. Iri gerageza ni uruziga rwa redox rugaragara n’amaso, kandi buri kintu abanyeshuri bashobora kubona, igihe cyo kunyeganyeza, ubushyuhe, concentration, gihura n’igice runaka cy’ubutabire buri gukorwa.

Imiterere ibiri y’irangi rimwe

Methylene blue yakorewe oksidasiyo ni urunigi rw’impeta ruringaniye kandi rufite charge nziza. Rwinjiza cyane urumuri ruri hagati ya 600 na 700 nanometres, ijisho rikabibona nk’ubururu bwijimye. Iyo miterere yombi n’imiterere yayo yo kwinjiza urumuri bisobanurwa muri amabwiriza ku miterere n’imiterere-shingiro bya methylene blue.

Reduction yongeraho electron ebyiri na proton imwe, igatanga leucomethylene blue: idafite charge, itaringaniye, kandi hafi ya yose idafite ibara. Mu gisubizo cya alkaline, half-reaction yandikwa MB+ + H2O + 2 e- ⇌ LMB + OH-. Iyi ntambwe ishobora gusubira inyuma yose. Ubururu busobanura imiterere yakorewe oksidasiyo, kutagira ibara bigasobanura imiterere yagabanyijwe, kandi nta miterere ya gatatu ikeneye gukurikiranwa, ari na byo bituma iri gerageza riba uburyo bworoshye bwo gutangira kwiga ubutabire bwa redox.

Uruziga: glucose iragabanya, oxygen ikongera gukora oksidasiyo

Icupa ririmo ibintu bitatu bikora: methylene blue, glucose, na alkali ikomeye, potassium cyangwa sodium hydroxide. Alkali ituma glucose ihinduka imiterere ya deprotonated ikora cyane kandi itanga electron ku irangi:

reducing sugar + MB (ubururu, yakorewe oksidasiyo) -> oxidised sugar products + LMB (idafite ibara)

Iyi ntambwe itinda ni yo ikuraho ibara igihe icupa riteretswe. Glucose ni yo donor ikoreshwa kandi irashira. Irangi ryo ritwara electron gusa, bityo udutonyanga duke dushobora gukorera icupa ryose. Inyandiko za kera zo mu mashuri zivuga ko glucose ihinduka gluconic acid. Icyo gisobanuro kigufi gishobora guhanura ibyo tubona, ariko abigisha bagomba kumenya ko kituzuye: isesengura rya mekanizime ryasohotse muri Royal Society Open Science rikurikirana oksidasiyo inyura kuri enediolate ikora cyane ikagera kuri dicarbonyl icikamo acide nto.

Kunyeganyeza bihindura icyo amaso abona. Kunyeganyeza bituma oxygen iva mu mwuka wafashwe mu mwanya uri hejuru y’amazi igashonga, maze oxygen ikongera gukora oksidasiyo ku irangi ryagabanyijwe:

LMB (idafite ibara) + O2 -> MB (ubururu) + reduced oxygen products

Iyo riteretswe, oxygen yashonze irashira, glucose ikongera kugabanya irangi, maze ibara rigenda rishira. Mu ruziga rwinshi, ubutabire rusange buba ari oksidasiyo y’isukari ikorwa n’umwuka, irangi rikomeza kuzenguruka ridahindutse nk’umuhuza wa redox. Ni umuhuza aho kuba catalyst nyakuri, kuko oksidasiyo y’isukari ishobora gukomeza n’iyo irangi ridahari, kandi gushira kw’ibara si decomposition: irangi ryangiritse ntiryashobora kongera kubyutswa no kunyeganyeza. Ku buryo bwo kubika neza stock z’irangi hagati y’amagerageza, reba inyandiko ku ikoreshwa no kubika ibisubizo bya methylene blue.

Uburyo bwo gukora igerageza rigenzurwa

Iri ni igerageza rigomba gukorwa rigenzurwa, si igikorwa cyo mu rugo. Alkali isaba kurinda amaso, kwambara uturindantoki, no kugira umwigisha ushinzwe gutegura no gusukura. Uburyo bubiri bwanditswe bufite imiterere imwe ariko bugatandukana ku gipimo.

Urupapuro rw’amabwiriza rwa demonstration yasohowe n’ishami ry’ubutabire rya Indiana University rukoresha hafi 5 percent potassium hydroxide, 4 percent glucose, na 1 percent aqueous methylene blue. Suka ingano zingana z’ibisubizo bya alkali na glucose mu icupa ribonerana rya 250 cyangwa 500 millilitre kugeza ryuzuye hagati, usige igice gisigaye nk’umwanya w’umwuka. Ongeramo udutonyanga duke tw’irangi, funga, ushyireho kashe ku murongo wo gufungiraho, maze uritereke kugeza ubururu bushize. Uburyo bwa Royal Society of Chemistry bukoresha igitekerezo kimwe kuri flask ifunze ya 1 litre: 300 millilitres y’amazi, 10 grams za glucose, 8 grams za potassium hydroxide (cyangwa 6 grams za sodium hydroxide), hiyongereyeho millilitres nke za stock y’irangi rit dilute.

Mu gukora igerageza, nyeganyeza cyane. Ubururu bwuzuye buboneka mu masegonda make. Rambika flask hasi maze upime igihe ibara rimara rishira. Royal Society of Chemistry ivuga ko ushobora kubona uruziga rurenga makumyabiri kuri filling imwe. Ntuzigere wuzuza icupa kugeza ku munwa: hatabayeho umwuka wafashwe nta oxygen ibikwa ngo ishonge.

Ibyo kwitegereza, n’ibihindura igihe

Pima ibintu bitatu: kunyeganyeza kugeza habonetse ubururu bwuzuye (seconds), kuritereka kugeza ritagira ibara (up to a few minutes), n’umubare w’inshuro uruziga rusubirwamo mbere y’uko ubururu bugabanuka. Hafi y’impera ya buri gihe ibara rishira, reba hejuru y’amazi. Akenshi umurongo muto w’ubururu uguma hafi y’aho amazi ahurira n’umwuka, aho oxygen ikomeza kwinjira buhoro. Uwo murongo ni diffusion igaragara n’amaso.

Reaction y’icupa ry’ubururu ikurikiza empirical rate law yatangajwe hamwe n’uburyo bwa Royal Society of Chemistry: rate = k[MB oxidised][glucose]OH-. Buri term ishobora kugirwa igerageza ryo mu ishuri. Kongera glucose, alkali, cyangwa irangi bigabanya igihe ubururu bumara. Ubushyuhe bwihutisha gushira kw’ibara; flask ikonje ikora buhoro. Kunyeganyeza cyane bituma oxygen nyinshi ishonga, bityo ubururu bukamara igihe kirekire. Umwanya munini w’umwuka wongera igihe igerageza rimara. Iyo amaherezo uruziga rutangiye gucika intege kandi amazi agahinduka umuhondo, isukari iba yashize kandi side products zikaba zarabaye nyinshi. Iyo endpoint ubwayo ni igisubizo gikwiye kwandikwa.

Urupapuro rwo kwandikaho ibyo witegereje

Koporora iyi table mu makayi, umurongo umwe kuri buri trial. Uru rupapuro hamwe n’igishushanyo cya reaction kiri hejuru ni byo bikoresho by’iyi ngingo bishobora gucapwa.

Ibibazo byo guhanura, bisubizwa mbere ya buri trial:

• Icupa riba ari ubururu ako kanya nyuma yo kunyeganyeza. Ni iyihe miterere y’irangi yiganje, kandi ni iki cyayishyize muri iyo miterere?
• Icupa riteretswe maze ibara rigashira. Ni iyihe reaction iri gutsinda, kandi ni ikihe kintu kiri gukoreshwa kigashira?
• Nyuma y’uruziga rwinshi ubururu buragabanuka bugasa n’umuhondo. Wabubyutsa ukoresheje irangi, alkali, cyangwa glucose, kandi kuki?
• Shushanya ibara ugereranyije n’igihe mu ruziga rumwe. Erekana aho oxygen yinjirira mu gisubizo. Ibisubizo by’umwigisha: (1) methylene blue yakorewe oksidasiyo, yongeye gukorerwa oksidasiyo na oxygen yashonze ivuye mu mwuka wo hejuru; (2) reduction ikorwa na glucose, glucose igakoreshwa; (3) glucose, donor igabanya uruziga, kuko irangi rikomeza kuzenguruka ridahindutse; (4) kuzamuka vuba igihe cyo kunyeganyeza, kugabanuka buhoro igihe riteretswe, oxygen ikinjira gusa mu gihe cyo kuzamuka.

Andi magerageza afitanye isano akwiriye kuvugwa

Demonstration ya traffic light ikoresha indigo carmine mu mwanya wayo kandi igaca mu mabara y’umuhondo, umutuku, n’icyatsi bitewe no kongeramo oxygen. Izina green bottle rikoreshwa mu buryo butandukanye: rimwe na rimwe ku bwoko ubwo, ubundi ku formulations zifite icyatsi kurushaho nka sisitemu zikoresha ascorbic acid cyangwa sisitemu ya enzymatic cycling yasobanuwe na American Chemical Society. Vuga neza ubwoko buri ku meza kugira ngo abanyeshuri badahuriza hamwe ibyo babonye mu butabire butandukanye.

Umutekano n’imikoreshereze

Genzura igerageza igihe cyose. Koresha uburinzi bw’amaso ku miti ishobora kumeneka n’uturindantoki igihe ufata alkaline solution cyangwa unyeganyeza vessel ifunze. Alkali iratwika, irangi rihindura ibara ry’uruhu n’imyenda, kandi dye stocks zateguwe muri ethanol zongeraho solvent ishobora gufatwa n’umuriro ku meza ya laboratwari. Gumana vessel ifunze igihe uyinyeganyeza. Nyuma, bika ibisubizo byakoreshejwe kugira ngo bitunganywe hakurikijwe amategeko ya laboratwari y’ikigo cyawe. Ibisabwa ku myanda ya alkaline irimo irangi biratandukanye hagati y’ibigo n’inzego z’amategeko, bityo ukurikize uburyo bwa laboratwari yawe aho gukura ubundi buryo ahandi.

Niba ushaka imibare aho kureba gusa impinduka z’ibara, quantitative assays za methylene blue zikomereza aho iri gerageza rigarukira.

Impamvu abarimu bakomeza gukoresha iri cupa

Flask imwe ihuriza hamwe ibitekerezo bine. Redox ihinduka ibara aho kuba definition gusa. Umuhuza werekana uburyo agace gato cyane k’ikintu kimwe gashobora kwerekana uko ibintu byinshi by’ikindi bihagaze. Kinetics itandukana na thermodynamics mu buryo bugaragara: oxygen iratsinda igihe kunyeganyeza kuyinjiza, glucose igatsinda igihe kuyinjiza bihagaze. Kandi diffusion, imwe mu nzira zituje cyane mu butabire, ni yo ituma byose bishoboka, kuko buri kumurika k’ubururu gutangirana na oxygen yambuka iva mu mwuka ikajya mu mazi. Igerageza rituma abanyeshuri bahanura, bapima igihe, kandi bagasobanura ibyo byose bakoresheje stopwatch na table rikwiye umwanya waryo ku meza ya laboratwari.