Qhov sib txawv tseem ceeb ntawm graphite thiab txhuas yog tias graphite tsis muaj tshuaj lom thiab ruaj khov, qhov txhuas yog tshuaj lom thiab tsis ruaj khov.
Graphite thiab txhuas muaj txiaj ntsig zoo hauv kev tsim cov xaum. Yav dhau los, cov xaum tau ua nrog cov hmoov txhuas, tab sis cov xaum niaj hnub tsis muaj txhuas txhua. Tam sim no lawv tau ua los ntawm graphite, uas muaj kev nyab xeeb thiab yog ib daim ntawv ntawm carbon.
Graphite yog dab tsi?
Graphite yog ib qho allotrope ntawm cov pa roj carbon muaj qhov ruaj khov, crystalline qauv. Nws yog ib daim ntawv ntawm cov thee. Tsis tas li ntawd, nws yog ib haiv neeg ntxhia. Native minerals yog cov khoom uas muaj ib qho tshuaj lom neeg uas tshwm sim hauv qhov tsis muaj kev sib txuas nrog lwm cov khoom. Ntxiv mus, graphite yog daim ntawv ruaj khov tshaj plaws ntawm carbon uas tshwm sim ntawm tus qauv kub thiab siab. Qhov rov ua dua ntawm graphite allotrope yog carbon (C). Graphite muaj hexagonal siv lead ua system. Nws tshwm nyob rau hauv ib tug hlau-dub mus rau steel-grey xim thiab kuj muaj ib tug metallic lustre. Cov xim streak ntawm graphite yog xim dub (xim ntawm cov hmoov ntxhia zoo).
Cov qauv siv lead ua graphite muaj cov kab ntsig honeycomb. Nws muaj cov nplooj ntawv graphene sib cais ntawm 0.335 nm nrug. Hauv cov qauv ntawm graphite, qhov kev ncua deb ntawm carbon atoms yog 0.142 nm. Cov pa roj carbon atoms khi rau ib leeg ntawm covalent bonds, ib qho carbon atom muaj peb covalent bonds nyob ib ncig ntawm nws. Lub valency ntawm carbon atom yog 4; Yog li, muaj plaub yam tsis muaj hluav taws xob nyob rau hauv txhua thiab txhua txhua carbon atom ntawm cov qauv no. Yog li ntawd, qhov no electron yog dawb mus tsiv teb tsaws, ua graphite hluav taws xob conductive. Ntuj graphite muaj txiaj ntsig zoo hauv refractories, roj teeb, steelmaking, nthuav graphite, nres hauv ob sab phlu, foundry ntsib, thiab lubricants.
Lead yog dab tsi?
Lead yog cov tshuaj muaj atomic tooj 82 thiab cov cim tshuaj Pb. Nws tshwm sim raws li cov tshuaj lom neeg hlau. Cov hlau no yog cov hlau hnyav thiab hnyav dua li feem ntau ntawm cov ntaub ntawv uas peb paub. Tsis tas li ntawd, txhuas tuaj yeem tshwm sim raws li cov hlau mos thiab malleable uas muaj cov ntsiab lus melting tsawg. Peb tuaj yeem txiav cov hlau no yooj yim, thiab nws muaj cov yam ntxwv xiav hint nrog rau cov xim silvery grey metallic tsos. Qhov tseem ceeb tshaj, cov hlau no muaj tus lej atomic ntau tshaj plaws ntawm cov khoom ruaj khov.
Lead yog cov hlau tsis zoo tom qab hloov pauv. Peb tuaj yeem piav qhia qhov tsis muaj zog hlau ua cim ntawm cov hlau lead siv nws qhov amphoteric xwm. E.g. txhuas thiab txhuas oxides teb nrog cov kua qaub thiab cov hauv paus thiab nyiam tsim covalent bonds. Cov hmoov txhuas feem ntau muaj +2 oxidation lub xeev ntawm cov hlau lead ntau dua li +4 oxidation xeev (+4 yog qhov feem ntau oxidation rau pawg 14 tshuaj lom neeg).
thaum xav txog cov khoom siv loj ntawm txhuas, nws muaj qhov siab ntom, malleability, ductility, thiab siab rau corrosion vim tias passivation. Cov hmoov txhuas muaj lub ntsej muag zoo sib xws hauv cov qauv cubic thiab qhov hnyav atomic, uas ua rau muaj qhov ntom ntom ntom ntom ntom ntom ntawm cov hlau feem ntau xws li hlau, tooj liab, thiab zinc. Thaum piv rau feem ntau cov hlau, txhuas muaj qhov melting point tsawg heev, thiab nws cov boiling point kuj yog qhov qis tshaj ntawm pawg 14 ntsiab.
Lead nyiam tsim txheej tiv thaiv thaum raug huab cua. Qhov feem ntau cov ntsiab lus ntawm cov txheej no yog lead (II) carbonate. Kuj tseem tuaj yeem muaj sulfate thiab chloride Cheebtsam ntawm txhuas. Cov txheej no ua rau cov hlau lead saum npoo zoo chemically inert rau huab cua. Tsis tas li ntawd, cov roj fluorine tuaj yeem hnov mob nrog cov hmoov txhuas hauv chav tsev kub kom tsim tau cov hmoov lead (II) fluoride. Muaj cov tshuaj tiv thaiv zoo sib xws nrog cov roj chlorine, tab sis nws yuav tsum tau cua sov. Tsis tas li ntawd, cov hlau lead yog resistant rau sulfuric acid thiab phosphoric acid tab sis reacts nrog HCl thiab HNO3 acid. Organic acids xws li acetic acid tuaj yeem yaj cov hlau lead hauv lub xub ntiag ntawm oxygen. Ib yam li ntawd, concentrated alkali acids tuaj yeem yaj ua cov plumbites.
Txij li cov hmoov txhuas tau raug cai nyob hauv Tebchaws Meskas xyoo 1978 los ua cov khoom xyaw hauv cov xim vim muaj tshuaj lom, nws tsis tau siv rau cov xaum qhuav. Txawm li cas los xij, nws yog cov khoom tseem ceeb siv rau kev tsim khoom xaum ua ntej lub sijhawm ntawd. Cov hmoov txhuas tau lees paub tias yog cov tshuaj lom neeg rau tib neeg. Yog li ntawd, tib neeg tau tshawb nrhiav cov khoom siv los hloov cov hlau lead nrog lwm yam los tsim cov xaum.
Qhov txawv ntawm Graphite thiab Lead yog dab tsi?
Graphite thiab txhuas yog cov tshuaj tseem ceeb vim lawv cov khoom muaj txiaj ntsig thiab kev siv. Qhov sib txawv tseem ceeb ntawm graphite thiab txhuas yog tias graphite yog nontoxic thiab ruaj khov heev, whereas lead yog lom thiab tsis ruaj khov.
Cov lus hauv qab no qhia txog qhov sib txawv ntawm graphite thiab txhuas.
Summary – Graphite vs Lead
Kev toxicity yog ib qho kev ntsuas tseem ceeb hauv kev siv cov khoom siv tshuaj hauv ib qho kev lag luam. Qhov sib txawv tseem ceeb ntawm graphite thiab txhuas yog tias graphite yog nontoxic thiab ruaj khov heev, whereas lead yog lom thiab tsis ruaj khov.
