Chinyorwa
Chiedzo chebhodhoro rebhuruu: kemisitiri, maitiro, uye zvinoonekwa
Bhodhoro rakajeka rakagara pabhenji. Rinoita semvura. Mumwe munhu anorizungunusa, uye mvura yacho inobva yava nebhuruu rakajeka zvikuru. Kana raiswa pasi, ruvara rwebhuruu runopera mukati meminiti imwe kana mbiri. Rizunguza zvakare uye bhuruu rinodzoka. Kuzadza kamwe chete kunogona kudzokorora izvi kanokwana makumi maviri kana kupfuura.
Vadzidzi vanowanzofungidzira kuti pane chinhu chakanga chakavanzwa mubhodhoro, kana kuti kuzunza kwakasanganisa marayer maviri. Fungidziro dzose idzi dzinoratidza nenzira inobatsira kuti hadzina kururama. Ruvara runobva kudhayi imwe chete, methylene blue, iri mumvura yose. Chinoshanduka ihuwandu hwemaelectron anotakurwa nedhayi. Kuratidzwa uku iredox cycle inooneka, uye chinhu chose chinogona kuonekwa nekirasi—nguva yekuzunza, tembiricha, concentration—chine hukama nechikamu chemakemisitiri acho.
Mafomu maviri edhayi imwe chete
Methylene blue yakaita oxidised isisitimu yemaringi yakati sandara uye ine charge yakanaka. Inotora chiedza zvakasimba panenge pa600 kusvika 700 nanometres, izvo ziso rinoona sebhuruu rakadzika. Mafomu maviri aya nemaspectra awo zvinotsanangurwa mugwara rechimiro nezvimiro zvemethylene blue.
Reduction inowedzera maelectron maviri neproton, zvichigadzira leucomethylene blue: isina charge, isina planar shape, uye inenge isina ruvara. Mu alkaline solution half-reaction inonyorwa MB+ + H2O + 2 e- ⇌ LMB + OH-. Danho iri rinogona kudzorerwa zvizere. Bhuruu rinoreva oxidised, kusava neruvara kunoreva reduced, uye hapana chimiro chechitatu chinofanira kuteverwa, izvo zvinoita kuti ichi chive chidzidzo chekutanga chakajeka cheredox chemistry.
Kutenderera kwacho: glucose inoreduce, oxygen inodzorerazve oxidation
Bhodhoro rine zvinhu zvitatu zvinoshanda: methylene blue, glucose, uye alkali yakasimba, potassium kana sodium hydroxide. Alkali inoita kuti glucose ipinde mumafomu anoshanda edeprotonated anopa maelectron kudhayi:
reducing sugar + MB (blue, oxidised) -> oxidised sugar products + LMB (colourless)
Danho iri rinononoka uye rinobvisa ruvara apo bhodhoro rakamira. Glucose ndiyo sacrificial donor uye inoshandiswa ichipera. Dhayi inongotakura maelectron, saka madonhwe mashoma anokwanira bhodhoro rose. Tsananguro dzekare dzemukirasi dzinoti glucose inoshanduka kuva gluconic acid. Pfupiso iyoyo inokwanisa kufanotaura zvinoonekwa, asi varairidzi vanofanira kuziva kuti haina kukwana: mechanistic analysis yakabudiswa muRoyal Society Open Science inotevera oxidation kuburikidza nereactive enediolate ichienda kudicarbonyl inopatsanuka kuita maacid madiki.
Kuzunza kunodzoreredza mhedzisiro inooneka. Agitation inonyungudutsa oxygen inobva mumhepo yakavharirwa muheadspace, uye oxygen inoitazve oxidation yedhayi yakareduced:
LMB (colourless) + O2 -> MB (blue) + reduced oxygen products
Kana bhodhoro rakasiiwa rakamira, oxygen yakanyungudutswa inopera, glucose inoreduce dhayi zvakare, uye ruvara runodzima. Mukutenderera kwakawanda, kemisitiri yese iri kuitika ndeyeoxidation yeshuga nemhepo, dhayi ichiramba ichitenderera isina kuchinjwa se redox mediator. Iyo mediator kwete catalyst chaiyo, nokuti oxidation yeshuga inogona kuitika pasina iyo, uye kupera kweruvara hakusi decomposition: dhayi yakaparadzwa yaisazokwanisa kudzorerwa nekuzunza. Kuti uchengete dye stocks dzakagadzikana pakati pekuratidzwa, ona zvinyorwa zvekubata nekuchengetedza methylene blue solutions.
Maitiro ekuratidzwa kunotarisirwa
Uku kuratidzwa kunofanira kuitwa richitarisirwa, kwete chiitiko chemumba. Alkali inoda kudzivirirwa kwemaziso, magirovhosi, uye murairidzi anotarisira kugadzirira nekuchenesa. Mafomura maviri akanyorwa anobvumirana pamaitiro acho asi anosiyana pachiyero.
Pepa remirayiridzo riri shure kwekuratidzwa kwakabudiswa nedhipatimendi rekemisitiri reIndiana University rinoshandisa approximately 5 percent potassium hydroxide, 4 percent glucose, uye 1 percent aqueous methylene blue. Durura mavhoriyamu akaenzana ealkali neglucose solutions mubhodhoro rakajeka re250 kana 500 millilitre kusvikira razara nehafu, uchisiya imwe nzvimbo seair headspace. Wedzera madonhwe mashoma edhayi, vhara, nama nzvimbo yekuvharira, wozorisiya rakamira kusvikira bhuruu rapera. Maitiro eRoyal Society of Chemistry anokudza pfungwa imwe chete kusvika kuflask ine stopper ye1 litre: 300 millilitres emvura, 10 grams eglucose, 8 grams epotassium hydroxide (kana 6 grams esodium hydroxide), pamwe nemillilitres mashoma edilute dye stock.
Pakuita, zunza nesimba. Bhuruu rakazara rinobuda mukati memasekondi. Isa flask pasi uye yera nguva yekupera kweruvara. Royal Society of Chemistry inotaura nezvekutenderera kunodarika makumi maviri pakuzadza kamwe chete. Usambozadza bhodhoro kusvika kumuromo: pasina mweya wakavharirwa hapana oxygen reserve yekunyunguduka.
Zvekucherechedza, uye zvinochinja nguva
Yera zvinhu zvitatu: kuzunza kusvika rava bhuruu rakazara (seconds), kumira kusvika risina ruvara (up to a few minutes), uye huwandu hwekutenderera bhuruu risati ratanga kushaya simba. Pedyo nekuguma kwekupera kweruvara kwega kwega, tarisa pamusoro pemvura. Layer nhete yebhuruu inowanzosara paair interface, apo oxygen inoramba ichipinda nediffusion. Mutsetse iwoyo unoita kuti diffusion ioneke.
Blue bottle reaction inotevera empirical rate law yakataurwa pamwe nemaitiro eRoyal Society of Chemistry: rate = k[MB oxidised][glucose]OH-. Chikamu chimwe nechimwe chinogona kushandiswa sechiedzo chemukirasi. Glucose yakawanda, alkali yakawanda, kana dhayi yakawanda zvinopfupisa nguva yebhuruu. Kupisa kunokurumidzisa kupera kweruvara; flask inotonhora inononoka. Kuzunza nesimba zvikuru kunonyungudutsa oxygen yakawanda, saka bhuruu rinogara kwenguva refu. Headspace yakakura inowedzera nguva yekushanda. Kana kutenderera kwazopedzisira kwava kushaya simba uye mvura yava yero, shuga inenge yapera uye side products dzinenge dzawanda. Endpoint iyoyo pachayo imhedzisiro yakakodzera kunyorerwa.
Pepa rekunyorera zvinoonekwa
Kopa tafura iyi mumabhuku, row imwe patrial. Pepa iri pamwe nedhayagiramu yereaction iri pamusoro ndizvo zvinhu zvinogona kuprintwa zvechinyorwa ichi.
| Trial | Condition changed | Shake time (s) | Time to full blue (s) | Time to colourless | Notes (colour depth, temperature) |
|---|---|---|---|---|---|
| 1 | baseline | ||||
| 2 | |||||
| 3 |
Mibvunzo yekufanotaura, inopindurwa trial imwe neimwe isati yatanga:
- Bhodhoro riri bhuruu pakarepo mushure mekuzunza. Ndeipi dye form iri kuwanda, uye chii chakaiisa mumamiriro iwayo?
- Bhodhoro rinomira uye ruvara runopera. Ndeipi reaction iri kukunda, uye ndechipi chinhu chiri kushandiswa chichipera?
- Mushure mekutenderera kwakawanda bhuruu rinova rakachenuruka uye rine yero. Ridzorere nedhayi, alkali, kana glucose, uye nei?
- Dhirowa ruvara maererano nenguva pakutenderera kumwe chete. Maka panopinda oxygen musolution.
Mhinduro dzemurairidzi: (1) oxidised methylene blue, yakaitazve oxidation nedissolved headspace oxygen; (2) reduction neglucose, glucose ichishandiswa; (3) glucose, limiting donor, nokuti dhayi inotenderera isina kuchinjwa; (4) kukwira kwakapinza pakuzunza, kuderera zvishoma nezvishoma pakumira, oxygen ichipinda panguva yekukwira chete.
Hama dzepedyo dzakakodzera kutaurwa
Traffic light demonstration inoshandisa indigo carmine panzvimbo payo uye inopfuura nemuyero, mutsvuku, negirini pamwe neoxygenation. Zita rekuti green bottle rinoshandiswa zvakasununguka: dzimwe nguva kureva variant iyoyo, dzimwe nguva kureva mafomura ane girini zvakanyanya akadai seascorbic acid systems kana enzymatic cycling system yakatsanangurwa neAmerican Chemical Society. Taura zita revariant iri pabhenji kuitira kuti vadzidzi vasabatanidze zvinoonekwa kubva kumakemisitiri akasiyana.
Kuchengeteka nekubata
Kutarisirwa nguva yose. Dziviriro yemaziso kubva kumakemikari anopfachukira uye magirovhosi pakubata alkaline solution kana pakuzunza mudziyo wakavharwa nestopper. Alkali inogona kupisa, dhayi inosvibisa ganda nemachira, uye dye stocks dzakagadzirwa muethanol dzinowedzera solvent inobatira moto pabhenji. Chengeta mudziyo wakavharwa paunenge uchizungunusa. Mushure mezvo, chengeta spent solutions kuti dzibatwe maererano nemitemo yerabhoritari yesangano renyu. Zvinodiwa pamarara ane alkali nedhayi zvinosiyana pakati pemasangano nematunhu emitemo, saka tevera maitiro anerabhoritari yenyu pane kutora maitiro kubva kune imwe nzvimbo.
Kana uchida manhamba panzvimbo pekuchinja kweruvara, quantitative assays dzemethylene blue dzinotangira panoperera kuratidzwa uku.
Nei vadzidzisi vachiramba vachishandisa bhodhoro iri
Flask imwe chete inounganidza pfungwa ina. Redox inova ruvara pane kungova tsananguro. Mediator inoratidza kuti chitsama chidiki chechinhu chimwe chinogona kuratidza zviri kuitika muhuwandu hukuru hwechimwe. Kinetics inoparadzaniswa nethermodynamics nenzira inooneka: oxygen inokunda apo kuzunza kuchiipa, glucose inokunda kana kupihwa kwayo kwamira. Uye diffusion, imwe yemaitiro akanyarara zvikuru mukemisitiri, ndiyo inoita kuti kuratidzwa kwese uku kuitike, nokuti kupenya kwega kwega kwebhuruu kunotanga neoxygen ichiyambuka kubva mumhepo ichipinda mumvura. Kuratidzwa kunobvumira vadzidzi kufanotaura, kuyera nguva, uye kutsanangura zvose izvi vachishandisa stopwatch netafura kwakakodzera nzvimbo yaro pabhenji.