Atoms ntawm tib hom tuaj yeem yog ib feem ntawm cov khoom sib txawv. Rau lub ntsiab lus qhia los ntawm lub cim "O" (los ntawm Latin lub npe Oxygenium), ob yam yooj yim tshuaj uas muaj nyob rau hauv cov xwm yog paub. Cov mis ntawm ib tug yog O2, thib ob yog O 3. Cov no yog cov kev hloov pauv ntawm cov pa oxygen (allotropes). Muaj lwm cov tebchaw uas tsis ruaj khov (O4 thiab O8). Kev sib piv ntawm cov molecules thiab cov khoom ntawm cov khoom yuav pab kom nkag siab qhov txawv ntawm cov ntaub ntawv no.
Kev hloov pauv allotropic yog dab tsi?
Ntau yam tshuaj muaj peev xwm muaj nyob rau hauv ob, peb lossis ntau daim ntawv. Txhua qhov kev hloov kho no yog tsim los ntawm atoms ntawm tib hom. Tus kws tshawb fawb J. Berzellius hauv xyoo 1841 yog thawj tus hu ua qhov tshwm sim no allotropy. Qhov qhib tsis tu ncua yog Ameslikas tsuas yog siv los qhia cov yam ntxwv ntawm cov qauv molecular. Piv txwv li, ob qho kev hloov kho allotropic ntawm oxygen paub, cov atoms uas tsim cov molecules. Tom qab ntawd, cov kws tshawb fawb pom tias kev hloov kho tuaj yeem yog cov muaju. Raws li cov tswv yim niaj hnub no, allotropy yog ib qho ntawm cov xwm txheej ntawm polymorphism. Qhov sib txawv ntawm cov qauv yog tshwm sim los ntawm cov txheej txheemtsim cov tshuaj lom neeg daim ntawv cog lus nyob rau hauv molecules thiab crystals. Cov yam ntxwv no feem ntau yog tshwm sim los ntawm cov ntsiab lus ntawm pawg 13-16 ntawm lub sijhawm lub sijhawm.
Yuav ua li cas sib txawv ntawm cov atoms cuam tshuam cov khoom ntawm cov teeb meem?
Allotropic kev hloov pauv ntawm oxygen thiab ozone yog tsim los ntawm atoms ntawm lub caij nrog tus lej atomic 8 thiab tib tus lej ntawm electrons. Tab sis lawv txawv ntawm cov qauv, uas ua rau muaj qhov sib txawv loj hauv cov khoom.
| Signs | Oxygen | Ozone |
| Kev sib xyaw ntawm cov molecule | 2 oxygen atoms | 3 oxygen atoms |
| Kev tsim kho |
|
|
| Aggregate xeev thiab xim | Cov pa roj tsis muaj xim lossis cov kua dej daj daj | Blue gas, xiav kua, tsaus liab doog khoom |
| Small | Nco | Ntxhais, nco txog nag xob nag cua, tshiab txiav nyom |
| melting point (°C) | -219 | -193 |
| Boiling point (°C) | -183 | -112 |
|
Density (g/l) |
1,4 | 2, 1 |
| dej solubility | me ntsis yaj | Zoo dua oxygen |
| Reactivity | Nyob rau hauv ib txwm muajruaj khov | Yooj yim decomposes tsim oxygen |
Cov lus xaus raws li cov txiaj ntsig ntawm kev sib piv: allotropic hloov pauv ntawm cov pa oxygen tsis txawv ntawm lawv cov khoom zoo. Cov qauv ntawm cov molecule yog tshwm sim nyob rau hauv lub cev thiab tshuaj lub zog ntawm cov khoom.
Puas yog cov pa oxygen thiab ozone zoo ib yam?
Tshuaj uas nws lub mis yog O2, pom nyob rau hauv cov huab cua, hydrosphere, lub ntiaj teb crust thiab cov kab mob nyob. Kwv yees li 20% ntawm cov huab cua yog tsim los ntawm diatomic oxygen molecules. Nyob rau hauv lub stratosphere, ntawm qhov siab ntawm 12-50 km ntawm lub ntiaj teb saum npoo, muaj ib txheej hu ua "ozone screen". Nws muaj pes tsawg leeg yog reflected los ntawm cov mis O3. Ozone tiv thaiv peb lub ntiaj teb los ntawm kev nqus cov rays txaus ntshai ntawm liab thiab ultraviolet spectrum ntawm lub hnub. Lub concentration ntawm ib yam khoom yog hloov tas li, thiab nws cov nqi nruab nrab yog qis - 0.001%. Yog li, O2 thiab O3 yog kev hloov pauv cov pa oxygen uas muaj qhov sib txawv loj hauv kev faib khoom.
Yuav ua li cas thiaj tau oxygen thiab ozone?
Molecular oxygen yog cov khoom yooj yim tshaj plaws hauv ntiaj teb. Nws yog tsim nyob rau hauv ntsuab qhov chaw ntawm cov nroj tsuag nyob rau hauv lub teeb thaum lub sij hawm photosynthesis. Nrog hluav taws xob tawm ntawm lub hauv paus chiv keeb los yog dag, lub diatomic oxygen molecule decomposes. Qhov kub ntawm qhov txheej txheem pib yog li 2000 ° C. Qee qhov tshwm sim radicals ua ke dua, tsim cov pa oxygen. Ib co active particle reacts nrog diatomic moleculesoxygen. Cov tshuaj tiv thaiv no ua rau ozone, uas kuj reacts nrog oxygen dawb radicals. Qhov no tsim diatomic molecules. Kev hloov pauv ntawm cov tshuaj tiv thaiv ua rau qhov tseeb tias qhov concentration ntawm atmospheric ozone hloov tas li. Nyob rau hauv lub stratosphere, tsim ib txheej uas muaj O3 molecules yog txuam nrog ultraviolet hluav taws xob los ntawm lub hnub. Yog tsis muaj daim thaiv tiv thaiv no, cov kab hluav taws xob txaus ntshai tuaj yeem ncav cuag lub ntiaj teb thiab rhuav tshem tag nrho cov ntaub ntawv txoj sia.
Allotropic hloov kho ntawm oxygen thiab sulfur
Cov tshuaj lom neeg O (Oxygenium) thiab S (Sulfur) nyob rau hauv tib pab pawg ntawm lub sij hawm lub sij hawm, lawv yog tus cwj pwm los ntawm kev tsim cov ntawv allotropic. Ntawm cov molecules nrog tus lej sib txawv ntawm cov sulfur atoms (2, 4, 6, 8), nyob rau hauv ib txwm muaj, qhov ruaj khov tshaj plaws yog S8, zoo li lub kaus mom hauv cov duab. Rhombic thiab monoclinic sulfur yog tsim los ntawm xws li 8-atom molecules.
Ntawm qhov kub ntawm 119 ° C, daim ntawv daj monoclinic tsim cov xim av xim av - kev hloov kho yas. Kev kawm txog kev hloov kho allotropic ntawm leej faj thiab cov pa oxygen yog qhov tseem ceeb hauv theoretical chemistry thiab cov kev ua ub no.
Hauv kev lag luam nplai, cov khoom oxidizing ntawm ntau hom yog siv. Ozone yog siv los tua cov pa thiab dej. Tab sis ntawm qhov siab tshaj 0.16 mg / m3, cov roj no txaus ntshai rau tib neeg thiab tsiaj txhu. Molecular oxygen yog qhov tseem ceeb rau kev ua pa thiab siv rau hauv kev lag luam thiab tshuaj. Carbon allotropes ua lub luag haujlwm tseem ceeb hauv kev lag luam.(pob zeb diamond, graphite), phosphorus (dawb, liab) thiab lwm yam tshuaj.
