curs chimia materialelor

8/20/2019 CURS Chimia Materialelor

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CUPRINS

1. ATOMI. STRUCTURA ATOMICĂ. CLASIFICAREA ELEMENTELOR..........81.1. DESCOPERIREA ELECTRONULUI...............................................................9

1.2. MODELUL STATIC AL ATOMULUI..........................................................101.3. MODELUL PLANETAR AL ATOMULUI..................................................111.4. CERCETAREA ÎNVELIŞULUI ELECTRONIC CU AJUTORULSPECTRELOR ATOMICE...................................................................................12

1.4.1. Spe!"#$ %!&'#$#( )e *()"&+e,.................................................................131.-. MODELUL CUANTIC AL ATOMULUI DE IDRO/EN DUPĂ OR ...........................................................................................................................1-

1.-.1. P&!#$%!e$e $#( &*".............................................................................1-1.-.2. C%$#$#$ "%e$&" &"(!e$&" pe"'(e...........................................................151.-.3. C%$#$#$ %"%!e"(!(($&" $(,(($&" pe!"%$e %$e *()"&+e,#$#( 6((,!e"p"e!%"e% $&" p"(, !e&"(% $#( &*"..................................................................171.-.4. Ep$(%"e% pe!"e$&" )e "%e # %:#!&"#$ !e&"(e( $#( &*"...................19

1.5. MODELUL ATOMIC OR;SOMMERFELD...........................................211.7. STRUCTURA ATOMICĂ INTERPRETATĂ PRIN TEORIA MECANICIICUANTICE..........................................................................................................23

1.7.1. Ap%"(


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3.1.2. Le+($e !e"'&*('(e(.................................................................................5-3.1.2.1. Le+e% e+%$(!@$#e,


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5.2. IONIAREA APEI...................................................................................1095.2.1. P"&)##$ (&,( %$ %pe(.............................................................................1105.2.2. Ep&,e,!#$ )e *()"&+e,. S%"% )e p % &$#


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10.3. PROTECIA METALELOR ŞI ALIAJELOR ÎMPOTRIVA COROIUNII............................................................................................................................178

10.3.1. A$e+e"e% "%


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PREFAŢĂ

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1. ATOMI. STRUCTURA ATOMICĂ.CLASIFICAREA ELEMENTELOR

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&,>&"' @"e(% materia nu este divizibilă la infinit ( e(!@ & $('(!@ % %e!e(%.P%"!(#$e$e >&%"!e '(( %"e %!(,+ %e%!@ $('(!@ %# >&! ,#'(!e )e e( atomi B+".

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#!$e"&? 6( D.I. Me,)e$ee? %# &,>("'%! e(!e,"6(!#$ e&$#$#( %$ I;$e% %#)e*( e"(% )e&pe"("($&" %"e %# )# $% e$#()%"e% !"#!#"(( %!&'(e )&?e)(,)#;e %!>e$ @ atomul nu este o particulă omogenă, compactă, impenetrabilă şiindivizibilă, ci este o particulă complexă, formată la rândul ei din mai multe alte

particule.S;% !%($(! %!>e$ @ =, &'p&(e$ e p&%!e =,&"'e%@ =, )e@"@"($e e$e!"(e =, +%e.

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Figura 1. Tub catodic de descărcări în gaze rarefiate

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e+%$ )e %"(,( e$e!"(e ,e+%!(?e Be$e!"&,( %6e%&((+. 3.

Figura 2. Difuzia particulelorα

printr-o foiţă metalică

Figura 3. Traiectoriile hiperbolice ale particulelor care trec prin ecinătatea unui nucleu.

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p"&p# primul model dinamic al atomului ,#'(! modelul planetar (,p(",)#;e)#p@ (!e'#$ &$%". D#p@ %e! '&)e$ %!&'#$ e!e %$@!#(! )(,!";#, ,#$e# e,!"%$

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1.4. CERCETAREA ÎNVELIŞULUI ELECTRONIC CUAJUTORUL SPECTRELOR ATOMICE

Spe!"e$e %!&'($&" "e>$e!@ )("e! '&)#$ =, %"e e >%e %&"&"'% #,#( ,#'@" )e $(,((e &,!(!#(e spectrul de linii al atomilor gazului "epe!(? %# spectrul atomic#Ap%"(%p!#$#( @ %!&'(( %>$%((,)

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ν $ Q 1λ = ν10;2 ';1 B1.1.

1.4.1. SPECTRUL ATOMULUI DE HIDROGEN

Î, %#$ *()"&+e,#$#( pe!"#$ =, )&'e,(#$ ?((($ B370; 700 ,' e!e >&"'%!)(, ("% 40 )e $(,(( e &,!(!#(e e"(% $#( %$'e". A&$& #,)e ,# e '%( )(!(,+$(,(( pe!"#$ )e $(,(( !"%,>&"',)#;e =, pe!"# &,!(,## B>(+. 4 %p%"e $('(!%e"(e( BLS.

Figura !. "pectrul atomului de hidrogen #seria lui $almer%.

L#,+('($e )e #,)@ pe,!"# >(e%"e $(,(e )(, e"(% %'(,!(!@ e p&! %$#$% #%:#!&"#$ >&"'#$e( $#( %$'e"

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1.5. MODELUL CUANTIC AL ATOMULUI DE HIDROGEN, DUPĂ OHR

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% >&! efectul fotoelectric extern. Ae! e>e! &,!@ =, e'((% )e e$e!"&,( ,#'((%!e %)(@ p&! ?%"(% ,#'%( )(&,!(,## B)e e. E1 E2 E3...E,.

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Figura &. "eriile spectrale ale atomului de hidrogen după $ohr.

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%"%!e"(e%@ limita seriei BL.S.. L('(!e$e e"(($&" pe!"%$e %# #"'@!&%"e$e?%$&"( R BL'%, R4 B%$'e" R9 BP%*e, R15 B"%e!! 6( R2- BP>#,).

1.5.4. E"PLICAREA SPECTRELOR DE RA!E " CU AJUTORULTEORIEI LUI OHR

%eoria lui or a permis explicarea spectrelor de raxe ! ale elementelor .R%e$e B?. 1.1 #,! "%)(%&(e! '#!%+e, p"&)#,)'#!%((,)

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∫ ='%

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1.%. STRUCTURA ATOMICĂ INTERPRETATĂ PRIN TEORIAMECANICII CUANTICE

1.%.1. APARIŢIA TEORIEI MECANICII CUANTICE

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Figura . nda electronică staţionară #unda de $roglie în atomul de hidrogen%.

De %(( &,$#(% @ %!#,( ,) %!&'#$ e %>$@ =,!";& !%"e e,e"+e!(@

!%&"'@ )e p&!#$%! )e#"+e %(( )(, p"&p"(e!@&!)e?&$!%!@ )e Ge",e" e(e,e"+ E"(, S*")(,+e" P.A.M. D("% M% &", G.P%#$( e!.

1.%.2. ATOMUL DE HIDROGEN ÎN CONCEPŢIA MECANICII CUANTICE

A6% #' ;% %"@!%! $% %% !e&"(e( 'e%,((( #%,!(e !@ &,ep( %e'@,%! # !"%(e!&"(% #,#( %!e$(! =, '(6%"e% % =, :#"#$

p@',!#$#(.D#p@ ,% !e&"(e e$e!"&,#$ )ep$%,)#;e =, :#"#$ ,#$e#$#( # & ?(!e@

>&%"!e '%"e e %>$@ =,!";#, (,!e"?%$ #"! )e !('p p"%!( =, &"(e p#,! %$ #,e("e+(#,( >e"(e % @"e( "%@ ,# e!e "(+#"& e+%$@ # 0-29 10;10 '.

Î, %e! >e$ 'e%,(% #%,!(@ )@ !e"'e,#$#( )e &"(!@ #, %$! e, )e@!e$ pe %"e $;% %?#! =, !e&"(% $#( &*". D#p@ ,% !e&"(e orbita sau traiectoriaelectronului capătă sensul unei regiuni (sfere) -n .urul nucleului =, %"e e$e!"&,#$e +@e6!e =, 'e)(e e$ '%( >"e?e,!. Se =,$&#(e6!e ,&


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,) , W 1 pe,!"# % )e&e( &"(!%$(( =,!"e e( e >&$&e %$!e !"e( ,#'e"e #%,!(e%"e ?&" >( )e"(e =, &,!(,#%"e.

1.%.5. NUMERE CUANTICE

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/umărul cuantic magnetic0 m , (,)(@ ,#'@"#$ )e &"(!%$( )(,!";#, #!"%!6( %"%!e"(e%@ !%"e% e$e!"&,($&" =, 'p#"( '%+,e!(e. E$e!"&,(( +"%?(!,) =,

:#"#$ ,#$e#$#( %!&'( "ep"e(,!@ ,(6!e #"e,


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Î, %e,e"(@ ,#$e#$ %!&'( %>$,)#;e =,

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De&%"ee #!"%!#$ s %p%"e =, !&%!e !"%!#"($e e$e!"&,(e %?,) )(>e"(!e?%$&"( n $% ,&!%"e% $#( e 'e,(+. 11.

Figura 11. ,rbitali s8 a - orbital 1s9 b - orbital 2s.

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,rbitali atomici ai primelor patru straturi electronice

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/umărul cuantic de spin , s. Pe $,+@ "&!%"$e%@. Ae%!@ (p&!e@ % >&! >@#!@

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%% )e "&!%&! &,>("'%!@ p"(,!"e %$!e$e )e !"#!#"% e$e!"&,(@ %%!&'($&". L&#$ #,#( e$e'e,! =, (!e' ,&!%! # #, ,#'@" ,#'(! număr de ordine

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31/190

1.(. OCUPAREA ORITALILOR ATOMICI CU ELECTRONI.STRUCTURA ÎNVELIŞULUI DE ELECTRONI A ATOMILOR

Î, %#$ %!&'($&" '%( +"e( )e! *()"&+e,#$ &"(!%$(( %!&'(( #,! &,!(!#(%e "epe!,) #"'@!&%"e$e p"(,(p((

a) Nivelurile energetice -n atomi se ocupă cu electroni -n ordinea crescândă

a energiei lor . D(, >(+#"% 1- "e#$!@ @ e &#p@ '%( =,!( &"(!%$#$ 1

%p&( 2 2p 3 3p 4 3) 4p - 4) -p e!.

b) &rincipiul de excluziune al lui &auli B192-. 7n orbital poate fi ocupat

de cel mult doi electroni caracterizaţi prin spin opus (electroni cuplaţi) .Ae! p"(,(p(# '%( p&%!e >( >&"'#$%! 6( %!>e$ -ntrun atom nu pot exista

doi electroni cu toate numerele cuantice identice, ei vor avea cel puţin un

număr cuantic diferit#

c) Regula lui 8und B192- Ae%!@ "e+#$@ e "e>e"@ $% &#p%"e% ,(?e$e$&"

e,e"+e!(e )e+e,e"%!e %)(@ % #!"%!#"($&" # '%( '#$e"(&". A6e%"e% !"%!(>(%!@ % e$e!"&,($&" e

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Figura 1&. ,rdinea cresc5ndă a nielelor energetice în atom.

Pe,!"# *()"&+e, (,+#"#$ @# e$e!"&, %>$,)#;e =, &"(!%$#$ 1 s &,>(+#"%&"'#$% &,>(+#"%(+#"%(e%"e pe"(&%)@ &#p%"e%!"%!#"($&" #!"%!#"($&" 6( &"(!%$($&" # e$e!"&,( e >%e %!>e$

1 1 s1;2 → 2e2 2e 2 s1;2 2 p1;5 → 10 Ne3 10 Ne 3 s1;2 3 p1;5 → 18A" 4 18A" 4 s1;2 3d 1;10 4 p1;5 → 35" - 35" - s1;2 4d 1;10 - p1;5 → -4e

5-4

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→ 85

R,7 85R, 7 s1;2 5d 1 - f 1;14 5d 2;10 7 p1;5 → Tabelul 3

"uccesiunea ocupării cu electroni a orbitalilor în primeledouă straturi #perioade%

E)*+*$-)

! S-/0- 1

S-/0- L 2 F/+)0*)*6-/768 2s 2 p9 2 p: 2 p;

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* 4 1s22s2

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C # 1s22s22 p2

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F ( 1s22s22 p5

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2. MOLECULE. LEGĂTURI CHIMICE

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&'p#6($&" (&,((. E% =,@ ,# p&%!e ep$(% e(!e,( =,$&#(! # #, %!&' )(, e%$%$!@ %!e+&"(e >@"@ @ *('e %"%!e"#$ )e %,%'$#%$ &'(,%e$ )e &'p#6( ,#e!e )e ,%!#"@ e$e!"&!%!(@ ( e )%!&"e6!e #,&" >&"%e p"(, '&)(>(%"e% !@"((#,#(% %# '%( '#$!&" e$e!"&,( %)(@ p"(, !"%,>e"%"e% !&!%$@ %# p%"((,) '%( '(@ )e! #'%e,e"+(($&" %!&'($&" &'p&,e,


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2.1. LEGĂTURA IONICĂ ELECTROVALENTĂ

2.1.1. TEORIA LUI &SSEL 1(1#

C&,>&"' %e!e( !e&"(( %!&'(( !(,) @ p(%")@ %# @ 6!(+e e$e!"&,( pe,!"# %@p@!% & !"#!#"@ e$e!"&,(@ !%($@ )e !(p +% "%" (%" (&,(( >&"'%(,) >&"'%"e% $e+@!#"(( (&,(e $% N%C$ e p&%!e %"@!% @ %"e $&

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1 s2 → , s2 , p5 → , s2 → , s2 , p5 ,d 10

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38/190

>&"'e%@ %e$e 6( @"#"($e B&'(,%&"'%"e% '&$e#$e$&" )e *()"&+e, $&" 6( %() $&"*()"( Be$e!"&,(( %'($&" p%"!e,e"( )e $e+@!#"@ e "ep"e(,!@ )(>e"(! pe,!"# % &%!e '%( (,e =, e?()e,&"'%"e% pe"e*(( )e e$e!"&,( )e $e+@!#"@

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40

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combinaţii este dată de numărul de pereci de electroni puşi -n comun . A!>e$%&!#$ e!e !"(&?%$e,! =, '&$e#$% % BN2.

E$e!"&,(( %"e ,# (%# p%"!e $% $e+@!#"( e ,#'e electroni neparticipanţi.Ae6!( e$e!"&,( e p&! "ep"ee,!% >(e p"(, p#,!e >(e p"(, $(,(#&"'% &'(,%e$ '&$e#$% )e F3 %?,) sextet =, $& )e octet electronic e!e%ep!&%"e )e e$e!"&,( =, !('p e '&$e#$% )e N3 %?,) &!e! e$e!"&,( e!e)&,&%"e )e e$e!"&,( )%!&"(!@ pe"e*(( )e e$e!"&,( ,ep%"!((p%,&"'%$e e (,)(@ p&$%"(!%!e%

3 N → F3 Î, !('p e $e+@!#"% &?%$e,!@ &(6,#(!@ %"e $& p"(, #,("e )e %!&'( 6( )#e $%

>&"'%"e% )e &'(,%&"'%"e )e &'(,%&! )%!@ )e A. Ge",e" B1893 6( p&%"!@ ,#'e$e )eteoria coordinaţiei. C&,>&"' %e!e( !e&"(( #,(( %!&'( )(p#, pe $,+@ valenţele

lor principale 6( )e #, %,#'(! ,#'@" )e valenţe secundare # %"e >&"'e%@$e+@!#"( *('(e )(!(,!e. Î, :#"#$ #,#( atom central #,! $e+%!e %# coordinate

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p"(, %e!e ?%$e,&"'e%@ prima sferă de coordinaţieYY ,&!%!@ p"(, p%"%,!ee p@!"%!e

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A!>e$ '&$e#$% (% ,%6!e"e p"(, =,!"ep@!"#,)e"e% &"(!%$($&" %!&'(( #>&"'%"e )e orbitali moleculari &'#,( %'($&" %!&'( ee% e &,!(!#(e $e+@!#"%&?%$e,!@.

C%$#$e$e e>e!#%!e )e e(!$e" 6( L&,)&, p"(?(,) e,e"+(% '&$e#$e( )e 2 =,>#,e! # "e#$!%!e$eepe"('e,!%$e 6( e$e %"%!@ @ pe!e 90 a )(, e,e"+(% )e $e+@!#"@ )(,!"e e( )&( %!&'( p"&?(,e )(, *('#$ e$e!"&,($&" )e $% #, ,#$e# $% %$!#$ pe,!"# % ,# p#,e )(, p#,e"e% =, &'#, % e$e!"&,($&"YY.

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p"(,(p(($e +e,e"%$e %$e !#!#"&" $e+@!#"($&" &?%$e,!e. D(!"(#


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Î, %#$ *()"&+e,#$#( $% %"e %$#$e$e &"ep#,) "e#$!%!e$&" epe"('e,!%$e>&"'%"e% &"(!%$#$#( '&$e#$%" p&%!e >( =,%e e#%&"'%"e% '&$e#$e( e!e ,e?&(e )e & >#,(e

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43/190

#,)e 2 8 Ψ corespunde orbitalului de legătură∗Ψ

2 8 ; orbitalului deantilegătură (%" >%!&"#$ 1 2 ,#'(! factor de normare p"&?(,e )(, &,)((,e6!e >#,


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Figura 1. Formarea legăturii σ 8 a-dintr-un orbital s i unul p9

b- din doi orbitali p 6 .

N&"#$ e$e!"&,( e &,!(!#(e $e+@!#"% σ %"e & &,>(+#"% i p z .

Le+@!#"($e π %p%" =,!"e %!&'(( $e+%(+#"($e 20 21 6(22 e p"e(,!@ $e+@!#"($e σ 6( π =, )(?e"e '&$e#$e % F 2O 6( N2.

Figura 2. Formarea legăturiiσ

în molecula de


45/190

Figura 21. ?egăturile coalente în molecula de apă.

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O/>7-0)7 +)*6)0/7 @7>/77;0B7. F&"'%"e% $e+@!#"(( &?%$e,!e =, &'p#6((&"+%,(( % 6( =, &'(,%&"'%"e% $e+@!#"(( =, '&$e#$% )e *()"&+e,.

Figura 22. ?egăturileσ

iπ

în molecula de azot.

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46/190

%"&,#$ e!e !e!"%&?%$e,!. Aee%6( ,e&,&")%,(+#"%e$ =,! )(, )&( %# '%( '#$&"'@ 6( e,e"+(e 6(

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Figura 2!. Direcţiile celor patru orbitali #alenţe% ale ; hibridizat sp1 .

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Figura 2&. ?egătura triplă în acetilenă.

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2.5. LEGĂTURI PRIN FORŢE VAN DER =AALS

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3.1.2.2. LEGEA CONSTANŢEI SUMEI CĂLDURILOR DE REACŢIEHESS, 1'4&"'%"e %CO. C#,&,) @ %")e"e% @"#,e$#( $% CO2 p&%!e )e#"+e %!! )("e! ! 6( =,e!%pe e p&%!e "(e

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Figura 3&. Afectele termice într-o reacţie ce decurge direct sau prin faze intermediare

3.1.3. IMPORTANŢA IOLOGICĂ A FENOMENELOR TERMOCHIMICE

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3.2.1. PRINCIPIUL I AL TERMODINAMICII SAU LEGEA CONSERVĂRIIENERGIEI

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3.2.2. PRINCIPIUL II AL TERMODINAMICII

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4.3. LEGEA ACŢIUNII MASELOR

D%@ e &,()e"@ & "e%((e,e$ la reacţiile reversibile aflate -n ecilibru cimic raportul dintre

produsul concentraţiilor produşilor de reacţie şi produsul concentraţiilor

reactanţilor, fiecare din concentraţii fiind ridicată la o putere egală cu numărul demoli ce iau parte la reacţie, este constant la o temperatură dată#Le+e% %e$ #

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75


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(concentraţie, presiune, temperatură), atunci ecilibrul se deplasează -n sensul reacţiei care se opune constrângerii, diminuândo sau anulândo.

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5. SOLUŢII

5.1. NOŢIUNI GENERALE

S&$#&"'%!e )(,

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&$?%! %>$%!@ =,!";#, $(!"# )e &$#


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Figura 3'. ;urbele de solubilitate ale unor săruri în apă.

S)>7)7-0-*0 0;*)/ )76@7*. Jnfluenţa temperaturii# Sp"e )e&e("e )e #!%,%p! %"e '%"e ('p&"!%,e"(.

Jnfluenţa presiunii# S&$#($(!%!e% +%e$&" e!e >%?&"(%!@ )e "e6!e"e% p"e(#,(( &,>&"' $e+(( $#( G. e," 6( $e+(( $#( J. D%$!&,

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C#' '&$e#$e$e #!%,((,)(,?%"(%($ p"e(#,e% ee"(!%!@ )e #!%,( p#@ =, e?()e,%"% $(*()#$#( !&! %6% #' ,# p&%!e >( ('((%$@ e!e *e%(%,&>e"%!#$ )e #p"# C#2_FeBCN5` %"e % >&! &&"'% #,#( p"e(p(!%!(,&$#($.

Ap%"%!#$ # %"e e )e!e"'(,@ p"e(#,e% &'&!(@ ,#'(! osmometru % >&!&e>>e" )(,!";& %e'e,e% 'e'"%,@ "e%$(%!@ =, p&"((#,#( ?% )e e"%'(@. S;% #'p$#! ?%#$ # & &$#&! (,>("'%!@ =, %#$ % ,#'e"&%e 'e'"%,e%"e ,# >#,(+. 37 e &,!%!@ @ ,(?e$#$ $(*()#$#( )(, e$#$@ e "()(@ =, !# p,@ e

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D(?((#,($e )e pe !# pe"'(! (!("e% p"e(#,(( &'&!(e )("e! =, %!'&>e"e.

Figura 3+. Aidenţierea presiunii osmotice cu aButorul unui osmometru.

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%e!&"%. A!#,( ,) %,!(!%!e% )e %p@ e e e?%p&"@ e!e '%( '%"e )e! e% %"e p@!"#,)e =, e$#$e p"(, e,)&'&@ p$%,!e$e "epe!(?e e ?e!e:e 6( '&". D%!&"(!@%e!#( >e,&'e, xerofitele B+". eros e ; p2ton p$%,!@ ;%# %)%p!%! pe,!"# %!"@( =,!";#, 'e)(# # #'()(!%!e >&%"!e @#!@ B)e ee'p$# %!%ee$e 6(e#>&"(%ee$e !"&p(%$e.

5.2.1.1. LEGILE PRESIUNII OSMOTICE.

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p"e(#,e &'&!(@ 6( e +@e $% %ee%6( !e'pee"%!#"@ &,> =,!";& (,+#"@ $e+e %"e =( p&%"!@ ,#'e$e 6( %"e e e,#,e$#$ #"'@!&" presiunea osmotică a unei soluţii diluate de neelectrolit este egalăcu presiunea pe care ar exercitao substanţa dizolvată, dacă sar găsi -n stare de

gaz şi ar ocupa un volum egal cu volumul soluţiei.D(, %e!e $e+( "e#$!@ @ p"e(#,e% &'&!(@ % &$#(@ $% --&C. Ae!e!e'pe"%!#"( "@', &,!%,!e p,@ ,) !&%!@ '%% )e $(*() e !"%,>&"'@.

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88/190

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90/190

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92/190

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#"e,!#$ e$e!"( %# tripleţi ionici CA;C "epe!(? A;CA; % @"&" '(6%"e @!"ee$e!"&( )e?(,e '%( +"e&%(e. Ae'e,e% >&"'%((,) &'@#"@ % %%!e"(( &$#&$&e &e>((e,(@"($e epe"('e,!%$e %# %"@!%! @ '&)#$ )e %$#$ %$ $#( > e!e &"e!

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#,)e A e!e & &,!%,!@ )epe,)e,!@ )e ,%!#"% &$?e,!#$#( 6( )e !e'pe"%!#"@Bpe,!"# &$#((,) #!%,&>&"#$>&"'e%@ # &(+e,#$ &'p#6( B%(( @,#(% e$ %"e ,e#!"%$(e%@ %e$e. De %((&,$#(% @ &(+e,#$ e!e e$e'e,!#$ )e!e"'(,%,! %$ p"&p"(e!@@"@ &(+e, % C$ %# CN 6( )e( ,# &(+e,#$ ( *()"&+e,#$)e!e"'(,@ p"&p"(e!@(e%"e )(, e$e %?,) =,@ #, %"%!e" '%( '#$! %# '%( p#&! %p$(%!@ )e e$ $%)e>(,("e% %(($&" 6( %e$&" ='p"e#,@ # G. O!%$) 6( %$&"' %e!e( !e&"(( %((( #,! #!%,


95/190

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99


98/190

#!%,( #, %() '%( $%. Î, &$?e,e$ )%@ #!%,((

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SO2 SO2 SO32; SO2 #$>(! !(&,($

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99/190

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O O O OS O → OSO → OSO B5.8 O O OÎ, ee'p$e$e )%!e F3 6( SO3 #,! '&$e#$e )e>((!%"e =,

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100/190

p#,e"e =, &'#, "epe!(? >&"'%"e% #,e( &?%$e,((!%" =,!";&%e'e,e% pe"e*e. Le+@!#"% *('(@ e %e%@ pe %p"&p(e"e% e$&" )@ #!%,&%"!e '#$!e %$!e !e&"(( )%" %"e $% ",)#$ $&" ;%# )&?e)(! $('(!%!e.

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T*/70 7-/8 0 )7 V. G-+0 ?7 I. L77- B19-4 e %e%@ pemigrarea de ioni pe %"e e( & ,#'e ionotropă )e $% & #!%,e!@ p"&p"(e!@e!@ %(.T*/70 067;7)/ ?7 >0;*)/ /* ?7 +7 % $#( A.P. "e*&? B1977 e %e%@ pe "e%e,&'e,#$ %()&;%( ,# % >&! =,("',)#;$e %"e%$e =, p$# e p%"e @ %e!@ !e&"(e $@'#"e6!e pe )ep$(, 6( pe,!"# !&!)e%#,%%)e?@"#$ )ep"e >e,&'e,#$ %()&;%( %!! )e &,!"&?e"%!.

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sarcina sa, masa fiind negli.abilă. S;% !"% concluzia generală că electronul prin sarcina sa negativă este componenta bazică fundamentală a materiei iar -nvelişul electronic este sediul caracterului bazic al tuturor elementelor şi al combinaţiilor lor .

Î, e p"(?e6!e %"%!e"#$ %() protonul % ,#$e# %$ %!&'#$#( )e *()"&+e,

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103/190

(&,($&" # %:#!&"#$ >%!&"#$#( )e e"%,%"e σ, %$e @"#( ?%$&"( e e?%$#e%@ )#p@#,&#!e$e "e+#$( e'p("(e %$e $#( S$%!e". Î, %p"&('%(,(!%!e% pe,!"# e$e!"&,( e!e =, '@#"@ @)(>e"e,(,(!%!e% pe,!"# e$e!"&,( p"(,e,e"+(% %"e e )e+%:@ %!#,( ,) #, %!&' %ep!@ #, e$e!"&, =, !"%!#$ @# )e?%$e,(,(!%!e% pe,!"# e$e!"&,( % %!&'#$#( )e >$#&" B%"e e!e )e 3983J'&$ e+%$@ # 97- a %()(!%!e (%" %((!%!e% (&,#$#( F ; e+%$@ # )(>e"e,e!#%! %$#$e ,#'%( pe,!"# e$e'e,!e$e %$e @"&" %>(,(!@(,(!@e!@ >(e%"e e$e'e,! =, p%"!e =, "%p&"! # p&(


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C%#e$e >e,&'e,#$#( %()&;%( ,# e "e)# $% e$e !e?% p"e?@#!e )e!e&"(($e %,!e"(&%"e. E(!@ & '#$!(!#)(,e )e %#e =, p"(,(p%$ de natură energetică

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#.4. SĂRURI ÎN SOLUŢIE

#.4.1. HIDROLI!A SĂRURILOR

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%ee% e !"ee =, 'e'"#$ !,+ _2O` (,$#,)#;e =, ?%$&%"e% &,!%,!e( )ee*($("# # )e,#'("e% )e constantă de idroliză ; P

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C&,e,!"% ; c ; c ; ) )))) ZS1ZS =⋅=== B5.51De( gradul de idroliză creşte cu diluţia B)e>(,(


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Cplicaţie. Pe,!"# ee'p$(>(%"e% ,#'e"(@ % %$#$e$&" !e&"e!(e )e '%( #e (% #, %'e!e !%'p&, %() %e!(;%e!%! )e &)(# pe,!"# & &,e,!"%


119/190

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M

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%. NOŢIUNI DE CINETICĂ CHIMICĂ. CATALI!A

%.1. OIECTUL CINETICII CHIMICE

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?(!ee( )e "e%e$ "e%&"'@ =, #"#$ "e%&"'% p"&)#6(A → p"&)#6( B7.1-

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C1222O11 2O → C512O5 C512O5 %*%"&@ +$#&@ >"#!&@

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1 e!e &,!%,!% )e ?(!e@ % "e%e"e,! )e &")(,#$ "e%


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%.4. FACTORII CARE INFLUENŢEA!Ă VITE!A DE REACŢIE

V(!e% )e "e%$#e,( "(@ =, >&"'@ $&+%"(!'(@

129


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Figura 3. (ariaţia constantei Figura !. (ariaţia lgE înitezei de reacţie cu temperatura. funcţie de 1T.

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Figura !1. (ariaţia de energie prin mecanismul stării de tranziţie8 A r -energia medie a reactanţilor9 A p-energia medie a produilor9

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Figura !2. ;urbele energetice în reacţii necatalizate #H% i catalizate #HH%8 A r -energia medie a reactanţilor9 A p-energia produilor de reacţie.

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Figura !3. Iecanismul hidrogenării catalitice a etenei prin chemiosorbţia ambilor reactanţi #a% sau doar a etenei #b%.

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'. STAREA COLOIDALĂ A MATERIEI

'.1. DEFINIREA STĂRII COLOIDALE

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'e!%$e$&" e!.C&$&(( de asociaţie

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Tabelul 1;lasificarea sistemelor coloidale după metodele de preparare

De,#'("e% (!e'#$#(&$&()%$

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'.3. PREPARAREA SISTEMELOR COLOIDALE

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'.5. PROPRIETĂŢILE SISTEMELOR COLOIDALE

'.5.1. STAILITATEA COLOI!ILOR

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(. ELECTROCHIMIA. CONVERSIAELECTROCHIMICĂ DE ENERGIE

O"IDARE ŞI REDUCERE

(.1. NOŢIUNI INTRODUCTIVE

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C$2 2 → 2C$Oe"?,) ?%"(%e"(&%"@ )e?%$e,e$ =, "e%(e"#$ e &()e%@ !"e,) )e $% !%"e% )e &()%"e Fe 0 $% !@"($e )e &()%"e

Fe2 6( Fe3 p"(, &'(,%"e # $&"#$. D%" 6( =, p"&e#$ )e "e)#e"e p&! p%"!((p% 6(%$!e #!%,(e"#$ ;% &()%! # %&"'@ =, "e)#@!&" (%" "e)#@!&"#$ $% ",)#$ @# e!"%,>&"'@ =, &()%,! &,>&"' e*($("e$&"

O()%,! ,e; Re)#@!&" Re)#@!&" ; ,e; O()%,!

%#

++−+

+−−+

⇔−

⇔+, pB

2O()

p

2)Re

,'B

1)Re

'

1O()

,e

A,eA

Î,#',) e$e )@ "e%


153/190

e p&%!e "(e &,!%,!% )e e*($("#

`)`_ReO()_

`O()`_)_Re

``_A_

``_A_D

21

21

p'

, pB,'B

==++

++

curs chimia materialelor

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