Nitrogen dioxide

Nitrogen tshuaj caij nrog atomic 7 nyob 5 pab pawg neeg ntawm cov Mendeleev periodic system. Qhov no diatomic roj nyob rau hauv ib txwm tej yam kev mob ntawm sufficiently inert. Nyob rau hauv lub ntiaj teb huab cua, nws tso nyiaj rau peb lub quarters. Lub caij yus muaj los ntawm cov nram qab no oxidation xeev: -3, -1, 0, 1, 2, 3, 4, 5. Nws yog ib feem ntawm ntau lub tebchaw. Ib tug yog ib tug reddish-xim av lom roj (tsiag ntawv los ntawm muaj peev xwm mus thab plaub lub pa ib ntsuj av tau, yuav ua pulmonary edema ntawm END), muaj ib tug yam ntxwv ntse, pungent tsw - yog nitrogen dioxide. Cov mis yog NO2. Hniav puas loj 46,01 g / mol. Ceev 2,62 g / dm³. Ib kub npau npau taw tes 21 ° C. Thaum yaj nyob rau hauv dej reacts nrog nws. Lub refractive index ntawm 1.449 (nyob rau hauv 20 ° C).

Nitrogen dioxide plays ib qho tseem ceeb luag hauj lwm nyob rau hauv atmospheric chemistry, nrog rau cov tsim ntawm tropospheric ozone. Ib txhij, nws yog ib tug loj cua pollutant thiab intermediate nyob rau hauv lub muaj synthesis ntawm nitric acid, uas yog ua tsheej lab ntawm tons txhua xyoo. Qhov no yog ib qho ntawm ob peb nitrogen oxides (binary inorganic tebchaw ntawm nitrogen thiab cov pa) nrog oxidation:

• I - N2O nitrogen oxide;

• II - TSIS MUAJ nitrogen monoxide;

• III - dinitrogen trioxide N2O3;

• IV - NO2 nitrogen dioxide thiab dinitrogen tetraoxide N2O4;

• V - dinitrogen pentoxide, N2O5;

• trinitramide N (NO2) 3.

Nitrogen dioxide yog yooj yim liquefied. Nws yog hnyav dua cov huab cua. Nyob rau hauv tej yam kev mob NO2 tov (kwv yees li 1: 1) mus tsis muaj kob tshuaj (nws dimer) N2O4. NO2 Science News for KIDS yog zoo to taub.

Los ntawm cov tshuaj tiv thaiv nrog dej yog hydrolyzed, lub resulting ob tsim acid (cov pa roj nitrous thiab nitric): 2NO2 + H2O → HNO2 + HNO3.

Nyob rau hauv tshua nrog alkali ntsev yog tsim raws li no ob acids: 2NaOH + 2NO2 → NaNO2 + NaNO3 + H2O.

Nws yog ib tug muaj zog oxidant muaj peev xwm ntawm oxidizing SO2 rau SO3. Nyob rau hauv no txoj kev nws yog raws li vaj tse nitrous sulfuric acid. Cov nruab nrab NO2 ntau yam, xws li organic tebchaw, sulfur, carbon thiab phosphorus, hlawv.

Nitrogen dioxide yog feem ntau ua los ntawm oxidation ntawm nitrogen oxide atmospheric oxygen: O2 + 2NO → 2NO2

Nyob rau hauv lub laboratory, NO2 npaj nyob rau hauv ob kauj ruam: lub cev qhuav dej ntawm nitric acid rau dinitrogen pentoxide, uas yog ces thermally decomposed:

2HNO3 → N2O5 + H2O,

2N2O5 → 4NO2 + O2.

Raws li ib tug tshwm sim ntawm thermal decomposition ntawm ib co hlau nitrates kuj yuav npaj NO2:

2Pb (NO3) 2 → 4NO2 + 2PbO + O2.

Lub oxide peev xwm yuav tsim los ntawm reacting nitric acid (feeb meej) los ntawm cov hlau (e.g., tooj liab):

4HNO3 + Cu → 2NO2 + Cu (NO3) 2 + 2H2O.

Nyob rau hauv tus ntawm nitric acid (feeb meej) tin Ntxiv rau nitrogen dioxide, tin acid tsim raws li ib tug los ntawm-cov khoom:

4HNO3 + SN → H2O + H2SnO3 + 4NO2.

Ib co kev pab oxide N2O4 (IV) raug xa mus rau raws li nitrogen tetroxide. Tab sis qhov no yog ib tug misnomer, raws li cov tshuaj yeeb dej caw yog dinitrogen tetroxide. NO2 tshwm sim nyob rau hauv equilibrium nrog lub tsis muaj kob roj N2O4: 2NO2↔N2O4.

Vim qhov no tshuav nyiaj li cas yog exothermic, nws yog txav mus rau sab ntawm NO2 sov dua thiab nyob qis - ntawm N2O4. Deamer kis mus rau hauv lub khoom hauv lub xeev ntawm ib tug kub ntawm Rho tawm 11.2 ° C. Thaum ib tug kub ntawm 150 degrees decomposes: N2O4 → 2NO2, ces 2NO2 → 2NO + O2.

Nitric acid yog maj mam tawm NO2, uas muab tus yam ntxwv daj xim ntawm feem ntau ntawm cov kuaj ntawm no acid:

4HNO3 → 4NO2 + 2H2O + O2.

Nitrogen dioxide yog yooj yim nrhiav tau los ntawm tsis hnov tsw txawm nyob rau hauv uas tsis muaj ntau, nqus tau pa ntawm lub vapor yuav tsum tau zam. Ib tug tej zaum qhov chaw ntawm NO2 yog fuming nitric acid uas allocates NO2 ntawm kub saum toj no 0 degrees. lom cov tsos mob (pulmonary edema) feem ntau tshwm sim tom qab nqus tau pa uas tuag koob tshuaj ntawm ob peb teev. Muaj yog ib co pov thawj uas ntev-lub sij hawm raug NO2 ntawm ntau saum toj no 40-100 mg / m³ yuav txo tau mob ntsws muaj nuj nqi thiab ua rau kom txoj kev pheej hmoo ntawm kev ua pa cov tsos mob. Nyob rau hauv kev tshawb fawb ntawm tej zaum tsim ib qhov txuas ntawm lub concentration ntawm NO2 thiab me nyuam mos cia li tuag tam sid.

Nitrogen dioxide tsim nyob rau hauv feem ntau combustion dab qhov twg huab cua yog siv raws li lub oxidant.

Thaum tsa tau kub, lub nitrogen sib xyaws nrog rau oxygen mus rau daim ntawv nitric oxide: O2 + N2 → 2NO, ces tsis muaj yog oxidized nyob rau hauv huab cua mus rau daim ntawv dioxide O2 + 2NO → 2NO2:

1. Nyob rau hauv tej atmospheric concentration yog ib tug heev qeeb txheej txheem.

2. Cov feem ntau yuav qhov twg los ntawm NO2 yog internal combustion xyaw, thermal fais fab nroj tsuag thiab, rau ib tug tsawg raws li, sis plawv hniav mills.

3. Cua sov siv nkev thiab furnaces kuj qhov chaw ntawm no oxide. Yuav tsum tau nitrogen yog tswvcuab rau tshaj combustion huab cua, uas yog hloov dua siab tshiab rau nitrogen oxides sov siab.

4. Nyob rau hauv tsev neeg kerosene tso cua sov thiab cua sov siv nkev kuj qhov chaw ntawm NO2.

5. nitrogen dioxide generated ntawm atmospheric nuclear xeem (reddish xim mushroom huab).

6. Ib txhia ua liaj ua teb tej thaj chaw uas nws saum npoo ntau yuav ncav cuag 30 g / m³.

7. NO2 yog tseem lawm uas ua los ntawm xob quaj, los nag.