Hlau Qauv Part 3 - Txhua Yam
Txheem
Tom qab lithium, uas tau siv ntau ntxiv hauv kev lag luam niaj hnub no, thiab sodium thiab potassium, uas yog ib qho tseem ceeb tshaj plaws hauv kev lag luam thiab lub ntiaj teb nyob, lub sij hawm tau los rau tag nrho cov ntsiab lus alkaline. Ua ntej peb yog rubidium, cesium thiab franc.
Peb lub ntsiab lus kawg yog qhov zoo sib xws, thiab tib lub sijhawm muaj cov khoom zoo sib xws nrog cov poov tshuaj thiab ua ke nrog nws tsim ib pawg hu ua potassium. Txij li thaum koj yuav luag tsis muaj peev xwm ua ib qho kev sim nrog rubidium thiab cesium, koj yuav tsum txaus siab rau koj tus kheej nrog cov ntaub ntawv uas lawv hnov zoo li potassium thiab tias lawv cov tebchaw muaj tib yam solubility raws li nws cov tebchaw.
1. Leej Txiv ntawm spectroscopy: Robert Wilhelm Bunsen (1811-99) ntawm sab laug, Gustav Robert Kirchhoff (1824-87) ntawm sab xis
Kev nce qib thaum ntxov hauv spectroscopy
Qhov tshwm sim ntawm kev pleev xim cov nplaim nrog cov ntsiab lus ntawm qee cov ntsiab lus tau paub thiab siv hauv kev tsim cov foob pob hluav taws ntev ua ntej lawv raug tso tawm rau hauv lub xeev dawb. Thaum pib ntawm lub xyoo pua puv 1859, cov kws tshawb fawb tau kawm txog cov kab spectral uas tshwm nyob rau hauv lub teeb ntawm lub hnub thiab emissions los ntawm rhuab tshuaj compounds. Xyoo XNUMX, ob tug German physicists - Robert Bunsen i Gustav Kirchhoff - tsim ib lub cuab yeej rau kev kuaj lub teeb emission (1). Thawj spectroscope muaj ib qho yooj yim tsim: nws muaj ib tug prism uas cais lub teeb rau hauv spectral kab thiab eyepiece nrog lens rau lawv saib (2). Qhov txiaj ntsig ntawm spectroscope rau tshuaj ntsuam xyuas tau pom tam sim ntawd: cov khoom tawg mus rau hauv atoms ntawm qhov kub ntawm cov nplaim taws, thiab cov kab no tsuas yog cov yam ntxwv ntawm lawv tus kheej xwb.
2. G. Kirchhoff ntawm lub spectroscope
3. Metallic Cesium (http://images-of-elements.com)
Bunsen thiab Kirchhoff pib lawv txoj kev tshawb fawb thiab ib xyoos tom qab ntawd lawv tau evaporated 44 tons ntawm cov dej ntxhia los ntawm lub caij nplooj ntoos hlav hauv Durkheim. Cov kab tau tshwm sim nyob rau hauv cov sediment spectrum uas tsis tuaj yeem raug ntaus nqi rau ib qho chaw paub thaum lub sijhawm ntawd. Bunsen (nws kuj yog ib tug chemist) cais cov tshuaj chloride ntawm ib lub caij tshiab los ntawm cov sediment, thiab muab lub npe rau cov hlau uas muaj nyob rau hauv nws. Los ntawm raws li cov kab xiav muaj zog hauv nws cov spectrum (Latin = xiav) (3).
Ob peb lub hlis tom qab, twb nyob rau hauv 1861, cov kws tshawb fawb tau soj ntsuam cov spectrum ntawm cov ntsev deposit nyob rau hauv ntau nthuav dav thiab nrhiav pom muaj lwm yam nyob rau hauv nws. Lawv muaj peev xwm cais nws cov chloride thiab txiav txim siab nws cov atomic loj. Txij li cov kab liab tau pom meej meej hauv cov spectrum, cov hlau lithium tshiab tau muaj npe rubid (los ntawm Latin = tsaus liab) (4). Kev tshawb pom ntawm ob lub ntsiab lus los ntawm spectral tsom xam ntseeg chemists thiab physicists. Hauv xyoo tom ntej, spectroscopy tau dhau los ua ib qho ntawm cov cuab yeej tshawb fawb tseem ceeb, thiab kev tshawb pom tau los nag zoo li cornucopia.
4. Hlau rubidium (http://images-of-elements.com)
Rubid nws tsis tsim nws cov zaub mov, thiab cesium tsuas yog ib qho (5). Ob lub ntsiab. Cov txheej saum npoo ntawm lub ntiaj teb muaj 0,029% rubidium (17th qhov chaw nyob rau hauv cov npe ntawm cov ntsiab lus abundances) thiab 0,0007% cesium (39 qhov chaw). Lawv tsis yog bioelements, tab sis qee cov nroj tsuag xaiv khaws rubidium, xws li haus luam yeeb thiab qab zib beets. Los ntawm qhov pom ntawm lub cev, ob qho tib si hlau yog "potassium ntawm steroids": txawm softer thiab fusible, thiab txawm ntau reactive (piv txwv li, lawv ignite spontaneously nyob rau hauv huab cua, thiab txawm react nrog dej nrog ib tug tawg).
los ntawm nws yog cov feem ntau "hlau" (hauv tshuaj, tsis yog nyob rau hauv lub colloquial siab ntawm lo lus). Raws li tau hais los saum no, cov khoom ntawm lawv cov tebchaw kuj zoo ib yam li cov tshuaj analogous potassium.
5 Pollucite Tsuas yog Cesium Mineral (USGS)
hlau rubidium thiab cesium tau txais los ntawm kev txo lawv cov tebchaw nrog magnesium lossis calcium hauv lub tshuab nqus tsev. Txij li thaum lawv tsuas yog xav tau los tsim qee yam ntawm lub hnub ci hlwb (qhov teeb meem teeb meem yooj yim emits electrons los ntawm lawv qhov chaw), cov khoom tsim txhua xyoo ntawm rubidium thiab cesium yog nyob rau hauv qhov kev txiav txim ntawm ntau pua kilograms. Lawv cov tebchaw kuj tsis siv dav.
Raws li cov poov tshuaj, Ib qho ntawm cov isotopes ntawm rubidium yog radioactive. Rb-87 muaj ib nrab-lub neej ntawm 50 billion xyoo, yog li cov hluav taws xob tsawg heev. Qhov no isotope yog siv rau hnub tim pob zeb. Cesium tsis muaj ib txwm tshwm sim radioactive isotopes, tab sis CS-137 yog ib qho ntawm cov khoom fission ntawm uranium hauv nuclear reactors. Nws raug cais los ntawm cov roj siv hluav taws xob vim tias cov isotope no tau siv los ua qhov chaw ntawm gamma hluav taws xob, piv txwv li, txhawm rau rhuav tshem cov qog nqaij hlav cancer.
Nyob rau hauv Honor ntawm Fabkis
6. Tus neeg nrhiav pom lus Fab Kis - Marguerite Perey (1909-75)
Mendeleev twb tau pom tias muaj lithium hlau hnyav dua li cesium thiab muab nws lub npe ua haujlwm. Chemists tau nrhiav nws nyob rau hauv lwm yam lithium minerals vim hais tias, zoo li lawv cov txheeb ze, nws yuav tsum nyob ntawd. Ob peb zaug nws zoo li nws tau pom, txawm hais tias hypothetically, tab sis yeej tsis materialized.
Thaum ntxov xyoo 87, nws tau pom tseeb tias lub caij 1914 yog xov tooj cua. Nyob rau hauv 227, Austrian physicists tau ze rau nrhiav pom. S. Meyer, W. Hess, thiab F. Panet tau pom tsis muaj zog alpha hluav taws xob los ntawm actinium-89 (ntxiv rau ntau cov beta particles secreted). Txij li thaum tus naj npawb atomic ntawm actinium yog 87, thiab emission ntawm ib qho alpha particle yog vim "txo" ntawm lub caij mus rau ob qhov chaw nyob rau hauv lub sij hawm lub sij hawm, lub isotope nrog atomic tooj 223 thiab loj tus naj npawb XNUMX yuav tsum tau, txawm li cas los xij, alpha hais txog lub zog zoo sib xws (qhov ntau ntawm cov khoom hauv huab cua yog ntsuas proportionally lawv lub zog) kuj xa tawm ib qho isotope ntawm protactinium, lwm cov kws tshawb fawb tau pom tias muaj kev sib kis ntawm cov tshuaj.
Kev tsov rog sai sai tau tshwm sim thiab txhua yam tsis nco qab lawm. Nyob rau xyoo 30, particle accelerators tau tsim thiab thawj cov khoom siv dag zog tau txais, xws li astatium ntev-tos nrog atomic tooj 85. Nyob rau hauv cov ntaub ntawv ntawm lub caij 87, theem ntawm technology ntawm lub sij hawm tsis tso cai kom tau txais qhov tsim nyog tus nqi. khoom siv rau synthesis. Fabkis physicist ua tiav qhov kev npaj txhij txog Marguerite Perey, tub kawm ntawm Maria Sklodowska-Curie (6). Nws, zoo li cov neeg Austrian ib feem peb ntawm ib puas xyoo dhau los, tau kawm txog kev lwj ntawm actinium-227. Kev kawm txuj ci tau ua kom tau txais kev npaj dawb huv, thiab lub sijhawm no tsis muaj leej twg muaj kev tsis ntseeg tias nws tau raug txheeb xyuas thaum kawg. Tus neeg tshawb nrhiav npe hu nws fabkis hwm lawv lub tebchaws. Element 87 yog qhov kawg uas tau pom nyob rau hauv cov zaub mov, tom qab sawv daws yuav tau txais artificially.
Fabkis nws yog tsim nyob rau hauv sab ceg ntawm lub xov tooj cua series, nyob rau hauv ib tug txheej txheem nrog tsawg efficiency thiab, ntxiv, yog heev luv luv nyob. Qhov muaj zog tshaj plaws isotope nrhiav tau los ntawm Mrs. Perey, Fr-223, muaj ib nrab-lub neej ntawm tsuas yog 20 feeb (txhais tau tias tsuas yog 1/8 ntawm tus nqi qub tom qab ib teev). Nws tau raug xam tias tag nrho lub ntiaj teb tsuas muaj li ntawm 30 grams ntawm franc (ib qho kev sib npaug yog tsim los ntawm cov isotope decaying thiab cov isotope tsim tshiab).
Txawm hais tias pom ib feem ntawm cov franc tebchaw tsis tau txais, nws cov khoom tau kawm, thiab nws tau pom tias nws yog pawg alkaline. Piv txwv li, thaum perchlorate ntxiv rau cov tshuaj uas muaj franc thiab poov tshuaj ions, precipitate yuav radioactive, tsis yog cov tshuaj. Qhov kev coj cwj pwm no ua pov thawj tias FrClO4 me ntsis soluble (precipitates nrog KClO4), thiab cov khoom ntawm francium zoo ib yam li cov poov tshuaj.
Fabkis, cas nws yuav...
… Yog kuv tuaj yeem tau txais ib qho piv txwv ntawm nws pom ntawm qhov muag liab qab? Ntawm chav kawm, mos li siv quav ciab, thiab tej zaum nrog ib tug golden hue (lub cesium saum toj no nws yog mos heev thiab yellowish nyob rau hauv cov xim). Nws yuav yaj ntawm 20-25 ° C thiab vaporize ib ncig ntawm 650 ° C (kwv yees raws li cov ntaub ntawv los ntawm yav dhau los ntu). Tsis tas li ntawd, nws yuav muaj tshuaj lom neeg heev. Yog li ntawd, nws yuav tsum tau khaws cia yam tsis muaj kev nkag mus rau oxygen thiab noo noo thiab nyob rau hauv ib lub thawv uas tiv thaiv hluav taws xob. Nws yuav tsum tau maj nrawm nrog cov kev sim, vim hais tias nyob rau hauv ob peb teev yuav xyaum tsis muaj Fabkis sab laug.
Honorary lithium
Nco ntsoov cov pseudo-halogens los ntawm xyoo tas los lub voj voog halogen? Cov no yog cov ions uas coj zoo li anions xws li Cl- los tsis muaj-. Cov no suav nrog, piv txwv li, cyanide CN- thiab SCN moles-, tsim cov ntsev nrog cov solubility zoo ib yam li pawg 17 anions.
Lithuanians kuj muaj ib tug follower, uas yog ammonium ion NH. 4 + - ib yam khoom ntawm dissolution ntawm ammonia nyob rau hauv dej (cov tshuaj yog alkaline, txawm hais tias tsis muaj zog tshaj nyob rau hauv cov ntaub ntawv ntawm alkali hlau hydroxides) thiab nws cov tshuaj tiv thaiv nrog acids. Cov ion zoo ib yam ua rau cov hlau hnyav dua alkali, thiab nws txoj kev sib raug zoo tshaj plaws yog cov poov tshuaj, piv txwv li, nws zoo ib yam li cov poov tshuaj cation thiab feem ntau hloov K + hauv nws cov khoom ntuj tsim. Lithium hlau yog cov reactive heev uas yuav tau txais los ntawm electrolysis ntawm aqueous daws ntawm ntsev thiab hydroxides. Siv cov mercury electrode, cov hlau tov hauv mercury (amalgam) tau txais. Cov ammonium ion zoo ib yam li alkali hlau uas nws kuj tsim ib qho amalgam.
Nyob rau hauv cov chav kawm systematic tsom xam ntawm L.magnesium ion cov ntaub ntawv yog qhov kawg yuav nrhiav tau. Yog vim li cas yog qhov zoo solubility ntawm lawv cov chlorides, sulfates thiab sulfides, uas txhais tau hais tias lawv tsis precipitate nyob rau hauv qhov kev txiav txim ntawm yav tas los ntxiv reagents siv los txiav txim lub xub ntiag ntawm hnyav hlau nyob rau hauv cov qauv. Txawm hais tias ammonium ntsev kuj yog cov soluble heev, lawv raug kuaj pom thaum pib ntawm kev tshuaj xyuas, vim lawv tsis tiv taus cua sov thiab evaporation ntawm cov kev daws teeb meem (lawv decompose yooj yim heev nrog kev tso tawm ntawm ammonia). Cov txheej txheem yog tej zaum paub rau txhua leej txhua tus: ib qho kev daws teeb meem ntawm lub hauv paus muaj zog (NaOH los yog KOH) yog ntxiv rau cov qauv, uas ua rau tso tawm ammonia.
Xam ammonia Nws raug kuaj pom los ntawm kev hnov tsw los yog los ntawm kev siv ib daim ntawv universal moistened nrog dej rau lub caj dab ntawm lub raj. NH gas3 dissolves nyob rau hauv dej thiab ua rau cov tshuaj alkaline thiab tig daim ntawv xiav.
7. Kev kuaj pom ntawm ammonium ions: nyob rau sab laug, lub xeem strip tig xiav nyob rau hauv qhov kev txiav txim ntawm tso ammonia, nyob rau sab xis, ib tug zoo tshwm sim ntawm Nessler xeem
Yog tias kuaj pom ammonia los ntawm qhov tsis hnov tsw, nco ntsoov cov kev cai siv lub qhov ntswg hauv chav kuaj. Yog li ntawd, tsis txhob leas hla cov hlab ntsha, coj cov vapors ntawm koj tus kheej nrog lub kiv cua txav ntawm koj txhais tes thiab tsis txhob nqus cua "tag nrho hauv siab", tab sis cia lub aroma ntawm cov compound ncav cuag koj lub qhov ntswg ntawm nws tus kheej.
Lub solubility ntawm ammonium ntsev yog zoo ib yam li cov analogous poov tshuaj compounds, yog li nws yuav ntxias kom npaj ammonium perchlorate NH.4Ciaj4 thiab ib qho kev sib xyaw ua ke nrog cobalt (kom paub meej, saib cov ntu dhau los). Txawm li cas los xij, cov txheej txheem nthuav tawm tsis haum rau kev kuaj xyuas qhov me me ntawm ammonia thiab ammonium ions hauv cov qauv. Nyob rau hauv lub chaw soj nstuam, Nessler's reagent yog siv rau lub hom phiaj no, uas precipitates los yog hloov xim txawm nyob rau hauv lub xub ntiag ntawm ib tug kab ntawm NH.3 (7).
Txawm li cas los xij, kuv xav tawm tswv yim tawm tsam ua qhov kev ntsuam xyuas tsim nyog hauv tsev, vim tias nws yuav tsum siv cov tshuaj mercury lom.
Tos kom txog thaum koj nyob rau hauv ib lub chaw soj nstuam tshaj lij nyob rau hauv kev saib xyuas ntawm tus kws cob qhia. Chemistry yog fascinating, tab sis - rau cov neeg uas tsis paub nws los yog tsis saib xyuas - nws yuav ua tau txaus ntshai.
Saib kuj:
