Zvisungo, zvinongedzo, zvinongedzo?

Sangana neElectrochemistry Chikamu 5

Pamisangano yapfuura takaziviswa kune mienzaniso yakawanda yemaseru evoltaic - mamwe enhoroondo akakosha uye mamwe ari kushandiswa nhasi. Nyika yemaseru yakapfuma kwazvo, saka yave nguva yekusuma masisitimu asiri iwo anoratidzwa kusvika zvino.

Nonmetals inogonawo kuva hafu-masero

Chekutanga, kuyedza kunoda maviri magraphite electrode kubva kune yakashandiswa Leclanche zvinhu, zinc bromide ZnBr₂, sosi yemagetsi (yakadai sebhatiri re4,5V) uye mita inodiwa yemagetsi. Mu laboratori yeimba, hongu, hatizowani yakakurudzirwa zinc munyu, asi kwatiri inogona kubudirira kuchinjwa nemusanganiswa we potassium bromide KBr uye zinc (VI) sulfate ZnSO.₄. Isu tinounganidza seti inoumbwa nematanda maviri egraphite uye tinoabatanidza kubhodhi kuitira kuti ma electrode anyudzwe zvishoma mugirazi.

Isu tinosungira zvidimbu zvetambo kune electrodes, kunyanya kushandisa simbi yesimbi (saka, kana uchibvisa kubva mubheteri yekare, siya "caps" yendarira pamatanda egraphite). Isu tichaitawo diaphragm kubva pachidimbu chemakadhibhodi ane zviyero zvakagadziridzwa kune beaker ine simba re 50-100 cm.³ (kadhibhodhi inogona kuwedzera kubaiwa nepini).

Iye zvino tinopedza mamwe emunyu akataurwa mumvura, uye wozadza girazi nemhinduro yakagadzirirwa (5-10% yevasungwa). Isa chigadziko ne electrodes pamucheto wemudziyo, uye usungirire magumo ematare kune mahwendefa endarira ebheti flat (polarity haina basa panguva ino) uye chengetedza hurongwa hwakavakwa.

Nenguva isipi, sirivheri-grey inopenya layer inoiswa pane electrode yakabatana kune yakaipa terminal yebhatiri. Yakagadzirwa kubva zinc simbi. Iyo yero-brown ruvara rwemhinduro inoonekwa pedyo neyechipiri electrode yakabatana kune yakanaka terminal yebhatiri. Yemahara bromine ine ruvara pedyo negirafu tsvimbo. Mushure memaminitsi anenge mashanu, bvisa waya kubva pamagetsi ebhatiri. Uchishandisa voltmeter, kuyera voltage (iyo yakaipa yemamita yakabatana ne electrode yakavharwa nesimbi yesimbi).

Pasina kupinda mumaitiro anoitika panguva ye electrolysis (tichaakurukura pane imwe yemisangano inotevera), tinogona kugumisa kuti sero rakagadzirwa rine maelectrode maviri: zinc (zinc simbi yakaiswa pagraphite mune Zn solution.²⁺) uye bromine (mhinduro yemahara bromine uye bromide ion Br^?) Carbon inongova conductor yemagetsi (mukuita, zvinhu zvisingagadziriswi pasi pemamwe mamiriro ezvinhu, akadai se graphite neplatinum, zvinowanzoshandiswa se electrode zvinhu).

Tichabatanidza mutori wezvino kune electrodes here? girobhu remwenje rine simba rekushanda re 1,5 V (iyo polarity yezvibatanidza zvakare haina basa). Sezvo simba rinobviswa kubva muhurongwa, tinoona kunyangarika zvishoma nezvishoma kwesimbi yesimbi pane imwe electrode uye ruvara rweyero pane imwe. Zvinhu zvakamboburitswa zvinoita, zvichidzoreredza chimiro chazvo chepakutanga. Mhedzisiro yacho haina kunanga nekufambiswa kwemaerekitironi kuburikidza newaya yekubatanidza. Ichi ndicho chimiro che galvanic masero.

Ndeapi maitiro akaitika muhurongwa hwedu? Kune zinc electrode isu tinogona kupa maitiro equation:

 (-) Chitambi⁰ ? zinc²⁺ + 2e^-

Pane yechipiri electrode, yemahara bromine inoderedzwa kuita bromine anions:

 (+) Kwete.₂ + 2e^- , 2 Mabhuku^-

Saka, sero dhayagiramu iri sezvinotevera (tinosiya potassium uye sulfate (VI) ions, izvo zvisingabatanidzi mukuita):

 (-)C, Zn | ZnBr2aq? ZnBr2aq | C(+)

Hatidi kushandisa diaphragm muchitokisi. Zvisinei, kushandiswa kwayo kunodzivirira kutama kwebromine pedyo ne-zinc-coated electrode uye zvakananga kuita pakati pezvinhu.

Nonmetals inoumba hafu-masero sesimbi zvinhu. Iwe unongoda kushandisa conductor akanyudzwa mune yakakodzera mhinduro inozotora chikamu mukufambiswa kwemaerekitironi. Kune ma halogens, iwo akajairwa kugona ndeaya anotevera (electrode reaction yakafanana neyakapihwa bromine):

Polycell	F2/F?	Cl2/ Cl?	Br2/ Br?	I2/I?
E0 [IN]	+ 2,87	+ 1,36	+ 1,07	+ 0,54

Panyaya yefluorine, iyo inogona kukosha (yepamusoro-soro yevose yakatemerwa hafu-masero) yakaverengwa pane kuyerwa. Chikonzero, sepakaitika alkali uye alkaline pasi simbi, ndiko kuita kwechinhu chinoshanda nemvura.

redox cell

Pakuedza kunotevera tichagadzirira mhinduro dzinotevera: iron (III) chloride, FeCl₃ nehuwandu hwe5%, potassium iodide KI ine mutsara we 10% uye kumiswa kwemvura-starch. Sanganisa masendimita mashoma muchubhu yekuyedza³ munyu mhinduro, uye mushure mechinguva wedzera madonhwe mashomanana ekumisa starch. Iyo yakasviba ruvara rwebhuruu yezviri mukati inoratidza kuvepo kwemahara ayodhini. Mhedzisiro yakanyorwa ne equation:

 2Fe³⁺ + 2i^- ? 2Fe²⁺ +I₂

iron(III) cations oxidize iodide anions kune yemahara element, ichidzikisira kuita iron (II) ions.

Kuchinja kwemuvara wechiratidzo che starch kwakasimbisa kuvapo kweiodine particles, asi Fe cations inoumbwawo here?²⁺? Ngatiedze iyi hypothesis. Muedzo wechiratidzo chekuonekwa kwesimbi (II) cations ndeyekuita ne potassium hexacyanoferrate (III) K.₃[Fe(CN)₆], inowanzozivikanwa se potassium ferricyanide. Mushonga wacho unoumba makristasi matsvuku, kusiyana ne potassium ferrocyanide yezita rimwechete (potassium (II) hexacyanoferrate K.₄[Fe(CN)₆]) nemakristasi eyero ? ngatisavhiringa hukama huviri uhwu. Ngatidzokorore kuedza kwekare, asi panzvimbo yekumisa starch tichawedzera madonhwe mashomanana e1% solution ye potassium ferricyanide. Zvekare, zviri mukati memudziyo wekuita zvinoshandura rima rebhuruu nekuda kwemusanganiswa wakaoma unonzi Turnbull bhuruu:

 3Fe²⁺ + 2[Fe(CN)₆]^3- ? Kutenda₃[Fe(CN)₆]₂

Kune vasingatendi, ndinokurudzira kuyedzwa ne divalent uye trivalent iron salt. Isu tinowana tint yebhuruu chete mune yekutanga.

Iye zvino dira mishonga yakawanda yesimbi (III) chloride uye potassium iodide mumabheki maviri maduku ane hurefu hwe 50-100 cm.³. Mune imwe neimwe yemidziyo, inyura graphite electrode netambo yakasungirirwa (yakaiswa panzvimbo yakakodzera kuitira kuti irege kuwira mugirazi). Uyezve wedzera zvishoma kumisa starch kumudziyo ne potassium iodide solution. Kuti ugadzire sero iwe unozodawo kiyi ye electrolytic (yakaitwa panguva yeimwe yemisangano yapfuura? Mutsetse wepepa rekudzima rakanyikwa mumhinduro yeKNO yakanyatsokwana.₃) Migumo yezvinotungamira kubva kuma electrode yakabatana kune zviteshi zvemamita epasi rose akaiswa kuyera voltage.

Isu tinosarudza polarity yekubatana kwevoltmeter isu pachedu kubva pakuongororwa kweiyo equation yekuita kwesimbi (III) cations ine ayodhini anion, tinoona kuti ndeapi ayoni avanosiya uye ndeapi anogamuchira maerekitironi. Kuverengwa kwemamita kunosimbisa kushanda kwegalvanic cell. Zvadaro tinoshandura chigadziro kuchiyero chezvino. Idiki (pakurongeka kwemakumi mashoma emamA), saka hatifanire kushandisa chero imwe yekuwedzera inogamuchira (senge girobhu remwenje) kuchengetedza mudziyo kubva mukukuvadzwa. Chiitiko chekugadzirisa muhurongwa chinoratidzwa nekuumbwa kweruvara rwebhuruu rakasviba rakapoteredza electrode yakanyudzwa mugirazi ine mhinduro ye potassium iodide. Tinowedzera riini imwe potassium ferricyanide mhinduro kune iron(III) munyu shaker? zvakare mariri. Ngatinyorei pasi equations yemaitiro anoitika mumagirazi:

 (-)2I^- ? ₂ + 2e^-

(+)2Fe³⁺ + 2e^- ? 2Fe²⁺ 

 uye cell schematic:

(-) C | WHO_aq || FeCl_3aq | C (+)

Kuita kwakafanana kunoitika muchitokisi senge mushure mekusanganisa ma substrates mu test chubhu (yakakwana kuwedzera anodic uye cathodic maitiro pamativi), uye kupatsanurwa kwenzvimbo kweshanduko kunobvumira simba rema electron kutamiswa pakati pehafu yesero. kushandiswa.

Sero ratiri kuvaka rinonzi redox cell. Zita rakajairika, asi rinotsausa. Mushure mezvose, isu tinoziva kuti oxidation uye kuderedza maitiro anoitika mune yega link. Nzira yekuziva sei kutungamira kwe redox reaction (inoitwa zvese musero uye mu test tube)? Nzira yacho iri nyore:

1. Mumatafura e physicochemical tinowana zvipimo zvinogoneka zvehafu-masero anoenderana? yeFe system³⁺/ Fe²⁺ iyi +0,77 V; zvangu₂/I^?: +0,54 V.

2. Iyo hurongwa ine mukana wepamusoro ndeye oxidizing agent mukuita (cell-cathode), uye hafu-sero ine simba rakaderera? iyo anode yesero, kureva, iyo inoderedza.

3. Nekudaro, zvinofanirwa kuyeukwa kuti kune masisitimu ane mutsauko mudiki muhukoshero hwezvakajairwa zvinogoneka, mune dzimwe nguva mabasa anogona kudzoserwa (iyo chaiyo inogoneka inoenderana nekusangana kweiyo reagents).

Sero remafuta

Ngatiunganidzei hurongwa kubva pakuedza kwekutanga, tichitsiva chete mhinduro ye potassium bromide uye zinc (VI) sulfate ine 10% solution ye sulfuric acid (VI) H.₂SO₄. Mushure memaminitsi 1-2 e electrolysis (inoitika nekubudiswa kwegesi pama electrode), bvisa simba remagetsi uye, zvakanyatsonaka kuti usabvisa mabhubhu egasi kubva pamusoro pegraphite, kuyera voltage ne voltmeter. Link yakagadzirwa! Mushure mekushandura mudziyo kune yazvino kuyerwa modhi, unogona kuona kunyangarika kwemabhuru egasi pamusoro peiyo graphite electrodes panguva yekuita maitiro. Kana isu tikasapinda mune zvakadzama maitirwo akakonzera kuiswa kwemahara okisijeni uye hydrogen pama electrode, zvino maitiro ari muchitokisi anotaridzika seizvi:

 (-)2H2? 4 maawa⁺ + 4e^-

(+) The₂ + 4H⁺ + 4e^- ? 2 maawa₂O

Pakazara, kuita kwekubatanidza kwemvura kubva kune zvinhu kunoitika.

Iyo yakagadzirwa sisitimu muenzaniso wemafuta sero. Iko kushandurwa kwakananga kwesimba rekuita pakati pemafuta uye oxidizer kuita magetsi kunobatsira zvakanyanya kubva pakuona kwehupfumi hwekuita? Hapana chikonzero chekushandura kupisa kwekupisa kuita simba remhepo, iro rinongotyaira ma turbines. Hazvishamisi kuti zvirongwa zvakadaro zvakagadzirirwa kugadzirisa matambudziko emagetsi (uye tsvina imvura yakachena). Nekudaro, mutengo wezvinhu zvekuvaka uye kudiwa kwekugadzirwa kwehydrogen zvipingamupinyi zvikuru.

Kunyangwe masero emafuta akashandiswa kugadzira magetsi munzvimbo dzakanyanya tekinoroji senge spaceflight (mune mamwe maindasitiri, mutengo unotora chikamu chechipiri), nhoroondo yavo yakareba kwazvo. Yekutanga kushanda prototype yehydrogen-oxygen cell yakavakwa nemuumbi weBritish William Robert Grove muna 1839.

Chinyorwa chinopa marudzi akati wandei ezvekubatanidza akasiyana neakakurukurwa mumisangano yapfuura. Unoda zvimwe zvikamu here? Zvinetso chete zvezvirongwa izvi, izvo zvakakosha kwete chete sechitubu chesimba, zvinotsanangurwa. Zvisinei, kudiwa kwekuchengetedza hukuru hwemavara hunonzwisisika hunoita kuti zvisakwanise kukurukura nyaya dzakawanda dzinonakidza dzine chokuita nereferensi (Ndinokurudzira vaverengi vanofarira kuti vaite tsvakurudzo yavo pachavo). Muchikamu chinotevera chenhevedzano tichaongorora tafura yezvinokwanisa zvehafu masero. Pachavawo nezvinogoverwa zvezviitiko zvinofadza.

electronic application

redox cell

Imwe neimwe galvanic cell inopinda oxidation (paanode) uye kuderedza (pacathode). Nekudaro, mumakemikari jargon, masero eredox anotumidzwa semhando chaiyo yehurongwa.

Kuti uite kuyedza, iwe uchada mhinduro dze potassium iodide KI uye iron (III) chloride FeCl.₃ uye kumiswa kwemvura ye starch (upfu hwembatatisi). Iwe unozodawo kiyi ye electrolytic yakazadzwa neconcentrated solution ye potassium nitrate (V) KNO₃. Kana isu tisina kiyi, zvakakwana kupeta kakawanda chidimbu chepepa rematishu kana shinda yedonje yakanyikwa mumhinduro ye potassium nitrate.

Tichashandisa graphite tsvimbo kubva kuLeclanche masero akashandiswa semagetsi (mufananidzo 1). Migumo ye electrode ipfupi-yakatenderedzwa newaya uye yakanyudzwa mumabheki ane zvinogadziriswa zveKI (pamwe nekuwedzera kwekumisa starch) uye FeCl.₃. Pamusoro pezvo, isu tinosanganisa mhinduro mumagirazi nekiyi ye electrolytic kana imwe yeinotsiva (mufananidzo 2). Pashure penguva yakati, mitsetse yepepuru inotanga kuoneka mugirazi ine mhinduro ye potassium iodide (mufananidzo 3), zvishoma nezvishoma ichishandura mudziyo kuva rima (mapikicha 4 uye 5). Ichi chigadzirwa chechimiro chekusanganiswa kwemahara ayodhini mamorekuru ane starch mamorekuru. Iodine yakaumbwa semhedzisiro yeoxidation yeiodide anions pane anode yesero:

(-) Anode: 2I^- ? ₂ + 2e^-

Pane yechipiri electrode (cathode), kuderedzwa kwesimbi (III) ions kwakaitika:

(+) Katoda: 2Fe³⁺ + 2e^- ? 2Fe²⁺

Iyo redox cell yakagadzirwa muyedzo ine chirongwa chinotevera:

(-) C | WHO_aq || FeCl_3aq | C (+)

apo chiratidzo chekabhoni C chinoreva graphite electrode uye || ? electrolytic kiyi. Mhedzisiro yese muhurongwa ndeye oxidation yeanions I^- by Fe cations³⁺:

2Fe³⁺ + 2i^- ? 2Fe²⁺ +I₂

redox cell

sero yevasungwa

Pakuedza kwechipiri iwe uchada: mhinduro yemhangura sulfate (II) CuSO₄, magetsi emhangura, electrolytic key yakazadzwa neconcentrated solution ye potassium nitrate (V) KNO₃ uye universal counter. Zadza rimwe remagirazi neCuSO solution.₄uye imwe ine dilution yakafanana 1:100 (semuenzaniso, 0,5 cm³ Wedzera mhinduro yakatorwa kubva mugirazi rekutanga nemvura kusvika kuhuwandu hwe50 cm³) (Mufananidzo 6). Mushure mekunyudza waya dzemhangura mumagirazi uye nekuvhara dunhu nekiyi ye electrolytic, pima voltage pakati pemagetsi esero. Idiki? anenge gumi nemaviri kana akati wandei makumi emamiriyoni (mufananidzo 7).

Kuparara kwemhangura uye kunaya kwemvura kunoitika pama electrode:

(-) Anode: Cu⁰ ? With²⁺ + 2e^- (shoma concentrated solution)

(+) Cathode: Cu²⁺ + 2e^- ? With⁰ (more concentrated solution)

Mushure mekuwedzera equation yeese maelectrode process, zvinozoitika kuti zvachose hapana kemikari inoitika! Simba rekufambisa kuseri kwebasa resero inongova chishuwo chegadziriro yekuenzanisa kuwanda kwemagirazi ese ari maviri.