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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
CIMIA e!e #,% )(,!"e 6!((,#,)%'e,!%$e %$e ,%!#"((.A?,) % &(e! )e !#)(# #!%,&"'@ =, %$!e$e *('(%
pe"'(!e %!! #,&%6!e"e% $#'(( %"e ,e =,&,:&%"@ ! 6( !"%,>&"'%"e% e(.De %ee% *('(% e!e =,!$,(!@ =, !&%!e )&'e,(($e %!(?(!@&"'%&,)#$ )e #,&6!((,&"'% $% !#)e,&"'ee$% !#)e,( p%(&,%
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1. ATOMI. STRUCTURA ATOMICĂ.CLASIFICAREA ELEMENTELOR
E!%pe$e (!&"(e %$e )e?&$!@"(( (?($(%#,)@ # e!%pe$e )e>(,("(( 6(e$#()@"(( ,&(( %,!(( +"e( Le#(p 6( De'&"(! %# e'( & teorie ,#'(!@ atomistică
&,>&"' @"e(% materia nu este divizibilă la infinit ( e(!@ & $('(!@ % %e!e(%.P%"!(#$e$e >&%"!e '(( %"e %!(,+ %e%!@ $('(!@ %# >&! ,#'(!e )e e( atomi B+".
Atomos e ,# e p&%!e )(?()e. T&&"'@ 6( '(6%"e (%" &"p#"($e e)e&ee =,!"e e$e p"(, ,#'@"#$ >&"'% 6( '&)#$ #' #,! %"%,:%&"'@ 'e!%>((@
pe#$%!(?@ 6( ,%(?@ B%((( =,e$ A. A?&+%)"& pe %%$e+(( $#( /% L#% p"(?(,) &'(,%"e% e$e'e,!e$&" =, !%"e +%&%@ % %:#, $%&,$#(% @ e$e'e,!e$e %"e =, &,)($@ =, !%"e +%&%@ #,!>&"'%!e )(, '&$e#$e (%!&'(e. A$
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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.
De@"@"($e e$e!"(e =, +%e "%"e>(%!e "e%$(%!e =, !##"( %!&)(e B!##"($eC"&&e $% !e,(#,( =,%$!e )e -0 000 ?&$$#&"ee,$#&"ee,! %$!##$#( %!&)(. De&%"ee ,%!#"% "%e$&" %!&)(e ,# e '&)(>(@ p"(, *('%"e%'e!%$#$#( )(, %"e e!e &,>e
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Figura 1. Tub catodic de descărcări în gaze rarefiate
D#p@ )e&pe"("e% e$e!"&,#$#( %# >&! )e!e"'(,%!e 6( %$#$%!e p"(,(p%$e$e%$e %"%!e"(!(( masa (m), sarcina (e) 6( sarcina specifică (em).
A!>e$ J.J. T*&'&, B1897 % )e!e"'(,%! %"(,% pe(>(@ % e$e!"&,#$#(B%"(,% #,(!@!(( )e '%@ %# "%p&"!#$ e'
e' Q 17-8791011 C+;1
C#,&,) "%p&"!#$ e' ;% %$#$%! masa de repaus a electronuluim Q 910810;31 + )e #,)e "e#$!@ @ e$e!"&,#$ %"e & '%@ )e 1837 &"( '%(
'(@ )e! '%% %!&'(@ %&$#!@ % *()"&+e,#$#( %"e e!e )e 15710;27 +.Î, ee% e p"(?e6!e )('e,(#,($e e$e!"&,#$#( e &,()e"@ @ "%% % e!e )e
%p"&('%!(? 100 000 &"( '%( '(@ )e! "%% %!&'($&". Razele anodice sau canal B>(+. 1. e )ep$%e%@ )e $% %,&) p"e %!&) %#
%"(,@ p&(!(?@ 6( p&! >( )e?(%!e )e p$%% ,e+%!(?@ % #,#( &,)e,%!&". E$e #,!%$@!#(!e )(, "e!#"($e %!&'($&" )e +% %"e %# p(e")#! e$e!"&,( B#,! (&,( +%&6(
p&(!(?(.D%@ =, %$e% "%e$&" %!&)(e e p#,e & p$%@ #
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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.
11
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S#,! =,!&%"e )(, %$e% $&" %e$e p%"!(#$e %"e e )ep$%e%@ pe )("e&%(% 'e!%$(@. Pe %% epe"(e,&") %
p"&p# primul model dinamic al atomului ,#'(! modelul planetar (,p(",)#;e)#p@ (!e'#$ &$%". D#p@ %e! '&)e$ %!&'#$ e!e %$@!#(! )(,!";#, ,#$e# e,!"%$
=, :#"#$ @"#(% e =,?"!e e$e!"&,(( pe &"(!e ("#$%"e $% )(!%,e$ ,#'@"#$ )e &")(,e " %p@!@ & e',(>(%((@.Ce"e!@"($e #$!e"(&%"e %# &,>("'%! =, +e,e"%$ %e%!@ ('%+(,e % !"#!#"((
%!&'#$#( 6( %# pe"'( )e!e"'(,%"e% ,#'@"#$#( )e &")(,e " pe %$e epe"('e,!%$@
pe,!"# & e"(e )e 'e!%$e.C# %:#!&"#$ '&)e$#$#( p$%,e!%" %$ $#( R#!*e">&") ;%# ep$(%! #,e$e&'p&"!@"( %$e %!&'($&" $e+%!e )e p"&p"(e!@(%!@ % e$e!"&,($&" =, "&!("e% $&" =, :#"#$ ,#$e#$#(.
1.4. CERCETAREA ÎNVELIŞULUI ELECTRONIC CUAJUTORUL SPECTRELOR ATOMICE
Spe!"e$e %!&'($&" "e>$e!@ )("e! '&)#$ =, %"e e >%e %&"&"'% #,#( ,#'@" )e $(,((e &,!(!#(e spectrul de linii al atomilor gazului "epe!(? %# spectrul atomic#Ap%"(%p!#$#( @ %!&'(( %>$%((,)
&'%")%#,)%'e,!%$@ p"(, e'((% e,e"+(e( %&"(!e # >&"'@ )e "%)(%#$ %p%" # >&"'% $(,(($&" %'(,!(!e.
U, pe!"# )e $(,(( e!e >&"'%! )(,!";#, ,#'@" )e $(,(( pe!"%$e %"%!e"(%!e p"(, $#,+('e% )e #,)@ λ 6( >"e?e,
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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"
−=
λ 22
2 ,
1
2
1R 1 B1.2.
#,)e ,2W2 B(% ?%$&"($e 3 4 -... (%" R e!e &,!%,!% $#( R)e"+BRQ109577-8107 ';1.
Spe!"#$ *()"&+e,#$#( &,(e%"e e"(e =, &")(,e% L'%, B, 1Q1%$'e" B,1Q2 P%*e, B,1Q3 "%e!! B,1Q4 P>#,) B,1Q- (%" ,2 W ,1. Î, %e%!@>&"'#$@ T2 6( T1 &,!(!#(e termeni spectrali 6( %,#'e T2 e!e termen constant B%e$%6( pe,!"# >(e%"e e"(e (%" T1 termen curent Be '&)(>(@ pe,!"# >(e%"e $(,(e)(, e"(e.
F(e@"#( !e"'e, pe!"%$ =( &"ep#,)e #, %,#'(! ,(?e$ )e e,e"+(e %$%!&'#$#(. A!>e$ #, e$e!"&, (!#%! =,!";#, %!&' %>$%! =, !%"e% >#,)%'e,!%$@ ee%
e &"ep#,)e !e"'e,#$#( pe!"%$ # e% '%( '(@ ?%$&%"e e,e"+e!(@ p&%!e%&"( e,e"+(e !"e,) $% #, ,(?e$ e,e"+e!( #pe"(&". C,) e$e!"&,#$ !"ee )e $%
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#, ,(?e$ #pe"(&" )e e,e"+(e E2 $% #,#$ (,>e"(&" E1 %!&'#$ e'(!e e,e"+(% %&"(!@E2;E1 # >&"'@ )e $#'(,@. D(, !#)(#$ pe!"#$#( *()"&+e,#$#( "e#$!@ )e( @ =,%!&'( e(!@ ,(?e$#"( )e e,e"+(e )("e!e (%" !"ee"e% %!&'($&" )e $% #, ,(?e$e,e"+e!( $% %$!#$ %"e $& # e'((e %# %&"
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1.5. MODELUL CUANTIC AL ATOMULUI DE HIDROGEN, DUPĂ OHR
N(e$ &*" B1913 e$%&"%"e%@ #, , '&)e$ %!&'( p&",(,) )e $% $e+($e>(((( $%(e >&$&(,)#;e )e teoria cuantică a luminii % $#( M% P$%, 6( )e
teoria efectului fotoelectric e$%&"%!@ )e A$e"! E(,!e(,.%eoria cuantică %#p"% $#'(,(( % >&! e$%&"%!@ )e M% P$%, B1900 pe,!"#ep$(%"e% )(!"(#&"' !e&"(e( #%,!(e lumina prezintă caracter discontinuu,corpuscular . E% e!e %&"(!@ %# e'(@ )e &"p#"( =, '&) )(&,!(,## )e&%"eee!e >&"'%!@ )(, &"p##$( B+"@#,"e?e,e,&'e,e %"e %# p#!#! >( (,!e"p"e!%!e p"(, !e&"(% #%,!e$&"
% >&! efectul fotoelectric extern. Ae! e>e! &,!@ =, e'((% )e e$e!"&,( ,#'((%!e %)(@ p&! ?%"(% ,#'%( )(&,!(,## B)e e. E1 E2 E3...E,.
1-
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2. A!&'#$ p&%!e e'(!e %# %&"( e,e"+(e "%)(%,!@ ,#'%( %!#,( ,) !"ee)(,!";& !%"e !%e"(&%"@ '%( %p"&p(%!@ )e ,#$e# pe & &"(!@ #pe"(&%"@ '%( =,)ep@"!%!@ )e,#$e#. D#p@ #, !('p >&%"!e #"! B10;8 e$e!"&,#$ "e?(,e p"(, %$! pe &"(!%
!%
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22
22
2
222
e4
*,
" ?'
" ?'
π= B1.12
%#
'10-290,'e4
*," 102
22
22−⋅⋅=
π= B1.13
D%@ e =,$&#(e6!e , # ?%$&"($e 1 2 3...e &$%! pe & &"(!@ !%$@ pe&"(!% # ,#'@"#$ #%,!( ,1 6( "epe!(? pe e% # ,#'@"#$ #%,!( ,2 e,e"+(%e'(@ )e %!&' $% %$!#$ e$e!"&,#$#( )e pe &"(!% # , 2 pe e% # ,1 e!e )#p@ &*"e+%$@ # * ν. De(
−
π=
π−−
π−=−= ν
22
21
2
42
221
42
222
42
12,
1
,
1
*
'e2
*,
'e2
*,
'e2EE* Y B1.20
C#'
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Z ν=λ
= ν ν
=λ
"e#$!@
−=
−π=λ= ν 2
221
22
21
3
42
,
1
,
1R
,
1
,
1
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'e21Z B1.21
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#,)e >%!&"#$ &'#, R "ep"e(,!@ &,!%,!% $#( R)e"+ 6( e!e %$@!#(!@ $%",)#$ e( )(, #,e$e &,!%,!e ,%!#"%$e >#,)%'e,!%$e. P"(, =,$&#("e% %e!&"% #?%$&"($e $&" &*" % %$#$%! ?%$&%"e% &,!%,!e( R pe %"e %$'e" % &(+.-. A!#,( ,) !"%,(% pe ,(?e$#$ # ,Q2 %p%" $(,(( =, e"(% %$'e" B!"%!#$ # ,Q2 ;% ,#'(! ,(?e$ %# !"%! L 6( %6% '%( )ep%"!e!"%!#$ # ,Q3 ;% ,#'(! !"%! M %p&( N O P 6( [.
Figura &. "eriile spectrale ale atomului de hidrogen după $ohr.
Te"'e,#$ ,2 e!e ?%"(%($ =,!";& e"(e 6( (,)(@ ,(?e$#$ )e pe %"e %"ee$e!"&,#$ pe,!"# % "e?e,( )(, !%"e% e(!%!@ =, !%"e% (,((,(! B ∞→2n =, #"'% #,e(e(!@"( p#!e",(e % %!&'#$#( !e"'e,#$ #"e,! %$ $(,(e( )(, >&"'#$% B1.21 e%,#$e%@ (%" ,% "e$%
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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"&)#,)'#!%((,)
>&"'%!@ )(, )@ $(,(( %p"&p(%!e B)#$e!. C&'p%",) pe!"e$e %"%!e"(!(e %$e
e$e'e,!e$&" #e(?e =, (!e'#$ pe"(&)( e &e"?@ & )ep$%%"e % >"e?e,(+#"% 5 e "ep"e(,!@ ?%"(%(e%"e e"(e %!#,( ,) e (% pe &")&,%!@ Z ν 6( pe %(@ .
I,!e"p"e!%"e% pe!"e$&" )e "%e # %:#!&"#$ !e&"(e( $#( &*" % >&! )%!@ )e N. &e$. E$e!"&,(( )(, !##"($e C"&&e %"e &'%")e%@ #p"%>%#,) =, !"%!#"($e e$e!"&,(e%$e %!&'($&" 'e!%$(( ep#$,) e$e!"&,(( *(%" )(, !"%!#"($e e$e '%( %p"&p(%!e )e,#$e#. L&#"($e )e?e,(!e ?%%,!e #,! &#p%!e ('e)(%! p"(,
!"%,($%
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. L(,(($e pe!"e$&" )e "%e =, )ep$(,@ &,&")%,(%"%!e"(%!e p"(,!";& "e$%&"'#$e( e'p("(e % $#( %$'e" e!. C# !&%!e %e!e #ee '&)e$#$ %!&'( %$ $#(
&*" 6( !e&"(% % #%,!(@ %#p"% %!&'#$#( )e *()"&+e, ;%# )&?e)(! )(, '#$!e p#,!e )e ?e)e"e ('pe">e!e. O e"(e )e "(!(( %)#e !e&"(e( $#( &*" e "e>e"e%# =,
20
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p"(,(p%$ $% (,!"&)#e"e% # !&!#$ %"(!"%"@ )e @!"e %e!% % #%,!(>(@"(('&'e,!#$#( %,!(!@e$) e e!(, !e&"(% $#( &*" $% &"(!e e$(p!(e pe,!"# % p#,e )e %&")
%e%!@ !e&"(e # ,#'e"&%e$e "e#$!%!e epe"('e,!%$e &e$) % (,!"&)# )@ ,#'e"e #%,!(e numărul cuanticazimutal nϕ şi numărul cuantic radial nr . M&'e,!#$ %,!(!@( )e&'p#=, )@ &'p&,e,!e #,% )e;% $#,+#$ "%e( ?e!&%"e " Bmoment cinetic radial 6(
%$!% pe"pe,)(#$%"@ pe %e%!% Bmoment cinetic orbital . C&,)((%"e pe,!"# '&'e,!#$ (,e!( "%)(%$ e!e )%!@ )e (,!e+"%$%
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∫ ='%
'(,
"
"
" " *,)" p B1.27
(%" pe,!"# '&'e,!#$ (,e!( &"(!%$ )e (,!e+"%$%
∫ π
ϕϕ =ϕ2
0
*,) p B1.28
De&%"ee p"(, "&!("e% e$e!"&,#$#( # #, #,+*( 2π !"%(e!&"(% e =,*()e"e#$!@ @ pe"(&)((!%!e% e!e &,&'(!e,!@ %!! pe,!"# ϕ ! 6( pe,!"# " =,! e p&!%)#,% "e$%e$) #,e( &"(!e !%e$) ;% )&?e)(! =, #"! !('p ('pe">e!@ p"(,(,%p%(!%!e% e( )e % ep$(% & e"(e )e ,&( &e"?%( e*(?%$%! # #, '( #"e,! ("#$%" %"e !"e#(e @ +e,e"ee #, 'p '%+,e!(.S;% )&?e)(! @ '&'e,!#$ '%+,e!( %$ #,#( e$e!"&, =, '(6%"e% % pe &"(!@ e!e &'@"('e #%,!(>(%!@ 6( e!e e+%$@ # #, '#$!(p$# %$ #,#( '&'e,! '%+,e!(e$e'e,!%" ,#'(! magneton or ,&!%! # µ0
10 /e"+2739
'4
e* −⋅=π
=µ B1.30
=, %"e e e!e %"(,% e$e!"&,#$#( '; '%% )e "ep%# % e$e!"&,#$#( (%" ;?(!e% $#'(,(( =, ?().
A$!@ &,!"(#"e?e,
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1.%. STRUCTURA ATOMICĂ INTERPRETATĂ PRIN TEORIAMECANICII CUANTICE
1.%.1. APARIŢIA TEORIEI MECANICII CUANTICE
Ne%:#,#"($e !e&"(e( #%,!(e %# >&! =,$@!#"%!e &)%!@ # %p%"("%,e L( )e "&+$(e "e%!&"#$ %e!e( !e&"(( % %"@!%! @ e(!@& %,%$&+(e pe">e!@ =,!"e p"&p"(e!@
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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 =,$&#(e6!e ,&
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"ep"ee,!%!@ % >((,) )(>#%!@ =, :#"#$ ,#$e#$#( =,!";#, ,&" )e e$e!"((!%!e ,e+%!(?@(%" p"&%($(!%!e% )e e(!e,&((e %"%!e"#$ &"p##$%" >(e e$&,)#$%!&"(#. O"(#' p"(, p"&p"(e!@(#$!@e,&'e,e$e %!&'(e &,$#(($e )ep"(,e)(, !#)(#$ >e,&'e,e$&" '%"&&p(e.
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P"&p"(e!@$e =, %,#'(!e &,)(#,e$ =, 'e%,(% &,)#$%!&"(e & e',(>(%#,
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,) , W 1 pe,!"# % )e&e( &"(!%$(( =,!"e e( e >&$&e %$!e !"e( ,#'e"e #%,!(e%"e ?&" >( )e"(e =, &,!(,#%"e.
1.%.5. NUMERE CUANTICE
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Î, %e,e"(@ ,#$e#$ %!&'( %>$,)#;e =,
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,rbitali atomici ai primelor patru straturi electronice
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1.(. OCUPAREA ORITALILOR ATOMICI CU ELECTRONI.STRUCTURA ÎNVELIŞULUI DE ELECTRONI A ATOMILOR
Î, %#$ %!&'($&" '%( +"e( )e! *()"&+e,#$ &"(!%$(( %!&'(( #,! &,!(!#(%e "epe!,) #"'@!&%"e$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#
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Figura 1&. ,rdinea cresc5ndă a nielelor energetice în atom.
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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
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"uccesiunea ocupării cu electroni a orbitalilor în primeledouă straturi #perioade%
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S-/0- L 2 F/+)0*)*6-/768 2s 2 p9 2 p: 2 p;
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L7 3 1s22s1
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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#
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1 s2 → , s2 , p5 → , s2 → , s2 , p5 ,d 10
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>&"'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 $e+@!#"@
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combinaţii este dată de numărul de pereci de electroni puşi -n comun . A!>e$%&!#$ 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,!@.
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Î, %#$ *()"&+e,#$#( $% %"e %$#$e$e &"ep#,) "e#$!%!e$&" epe"('e,!%$e>&"'%"e% &"(!%$#$#( '&$e#$%" p&%!e >( =,%e e#%&"'%"e% '&$e#$e( e!e ,e?&(e )e & >#,(e
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#,)e 2 8 Ψ corespunde orbitalului de legătură∗Ψ
2 8 ; orbitalului deantilegătură (%" >%!&"#$ 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 $e+@!#"% σ %"e & &,>(+#"% i p z .
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Figura 2. Formarea legăturiiσ
în molecula de
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Figura 21. ?egăturile coalente în molecula de apă.
D(, >(+#"% 20 "e#$!@ @ '&$e#$% )e F p"e(,!@ & $e+@!#"@ &?%$e,!@ p&$%"@% !&(+#"% 21 "e(ee @ '&$e#$% %pe( %"e & !"#!#"@#,+*(#$%"@ B=,!"e e$e )@ $e+@!#"( σ e(!@ #, #,+*( )e 104&30 (%" =, >(+#"% 22e &e"?@ e$e !"e( $e+@!#"( &"(e,!%!e e(!e,!e =, '&$e#$% )e %&! 6( %,#'e &$e+@!#"@ σ 6( )@ $e+@!#"( π pe"pe,)(#$%"e =,!"e e$e.
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%"&,#$ e!e !e!"%&?%$e,!. Aee%6( ,e&,&")%,(+#"%e$ =,! )(, )&( %# '%( '#$&"'@ 6( e,e"+(e 6(
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A!&'#$ )e %"&, =, !%"e e(!%!@ %?,) &,>(+#"%&"' >(+#"(( 24
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Figura 2&. ?egătura triplă în acetilenă.
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E$e'e,!e$e )(, pe"(&%)% % 2;% # ,#'@" %!&'( '%( '%"e )e! %"&,#$#>e"@ *("()(%"e sp3 =, &'(,%(@ ,#'%( %"&,#$#( p"&p"(e!%!e%)e % >&"'% $e+@!#"( )#$e # e$ =,#6( # O 6( N ee% e &,!(!#(e #,% )(, %#e$eee,/77;8/7 6 0/-7670/*0 />7-0)7)/ d . A!&'(( e$e'e,!e$&" )(, pe"(&%)%
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("()(%"e% sp3d %"e 1- %"%!e" )e &"(!%$ s 3- %"%!e" )e &"(!%$ p 6( 1-%"%!e" )e &"(!%$ d .
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Î, !%e$#$ %$@!#"%! e p"e(,!@ +e&'e!"(% '&$e#$e$&" p&$(%!&'(e )e !(p#$A'E, =, %"e A "ep"e(,!@ %!&'#$ e,!"%$ %!&'(( $e+%7-0)7 +)*6)0/7 π *9-7?7 ?7 *)*6-/7 p *)60)7;0-7.S"(e"e% #,&" >&"'#$e *('(e ( pe,!%&?%$e,! )e&%"ee %" !"e#( @ e(!e =, !"%!#$ )e ?%$e,
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'%( '#$! %# '%( p#(e ( e$e e )e>% 6( e "e>% =, '&) &,!(,## #e$e!"&,( e p"&?(, )e $% %$&! e!(, =, =,!"e%+% '%@ % 'e!%$#$#( 6( e!e %e'@,@!&" # >e,&'e,#$ )e "e&,%,e$ =,! %!&'(( %)&p!@%6e@"($e e$e '%( @"%e =, e,e"+(e %"e &"ep#,) structurilor compacte. D#p@%e%!@ &,ep&"'% #, %!&' # %!&'(( ?e(,( 6( )e( )e ,#'@"#$ )e e$e!"&,( ,e#p$%e$ e ep$(@ )e e e$e'e,!e$e !"%,(
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2.5. LEGĂTURI PRIN FORŢE VAN DER =AALS
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C@$)#"% %"e =,&e"e,
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T"e#(e p"e(%! @ e(!@ & )e&e("e =,!"e @$)#"% )e "e%
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)e e', *('%!X pe,!"# >&"'%"e% )(, e$e'e,!e % 2OB$ ∆Q;5832 %$'&$ (%" pe,!"# )e&'p#,e"e% % !e"'(@ ∆Q5832 %$'&$.
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3.1.3. IMPORTANŢA IOLOGICĂ A FENOMENELOR TERMOCHIMICE
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O"+%,('#$ %,('%$ pe,!"# % e p#!e% =,!"ee"(!e$e "e%&"'@"( *('(e #,! =, +e,e"%$ )e ,%!#"@&()%!(?@ =, %"e p"&)#6(( #$!('( )e "e%@"@ (,!e"?e,@"@ p"&)#6(((,!e"'e)(%"( %# %$!e %pe!e %$e !@"($&" (,!e"'e)(%"e.
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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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>&"'#$%! )e @!"e e," Le C*!e$(e" B188- 6( F. "%#, B1885 %!>e$ când asupraunui sistem cimic aflat -n ecilibru se exercită o constrângere din afară
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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
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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"(.
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D(?((#,($e )e pe !# pe"'(! (!("e% p"e(#,(( &'&!(e )("e! =, %!'&>e"e.
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%e!&"%. A!#,( ,) %,!(!%!e% )e %p@ e e e?%p&"@ e!e '%( '%"e )e! e% %"e p@!"#,)e =, e$#$e p"(, e,)&'&@ p$%,!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.
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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 %$#$ %$ $#( > e!e &"e!
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$% donor de protoni )e6( e #,& #!%,(%"e e )@ "e%%@ % p"&e#$#( )e ,e#!"%$(%"e e% p#!,) >( #"'%!@ )e #, p"&e )e (&,(%"e %#)e & "e+"#p%"e '&$e#$%"@ % =, ee'p$#$ #"'@!&"
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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)(! $('(!%!e.
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sarcina sa, masa fiind negli.abilă. S;% !"% concluzia generală că electronul prin sarcina sa negativă este componenta bazică fundamentală a materiei iar -nvelişul electronic este sediul caracterului bazic al tuturor elementelor şi al combinaţiilor lor .
Î, e p"(?e6!e %"%!e"#$ %() protonul % ,#$e# %$ %!&'#$#( )e *()"&+e,
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#.4. SĂRURI ÎN SOLUŢIE
#.4.1. HIDROLI!A SĂRURILOR
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%ee% e !"ee =, 'e'"#$ !,+ _2O` (,$#,)#;e =, ?%$&%"e% &,!%,!e( )ee*($("# # )e,#'("e% )e constantă de idroliză ; P
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C&,e,!"% ; c ; c ; ) )))) ZS1ZS =⋅=== B5.51De( gradul de idroliză creşte cu diluţia B)e>(,(
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Re#$!@ )(, #$!('% "e$%e,&'e,#$#( )e *()"&$(@ e!e )e&e(! )e ('p&"!%,!@ pe,!"# %p"e(e"e% =,+"@6@'(,!e$&" *('(e =, &$ =, &$#&"'%!e )(, %'e!e#"( )e %() $% 6( & %"e %% # & %@ !%"e p"e#' 6( )(,!";& %@ $%@ 6( & %"e % % # #, %() !%"e )eee'p$#
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Cplicaţie. Pe,!"# ee'p$(>(%"e% ,#'e"(@ % %$#$e$&" !e&"e!(e )e '%( #e (% #, %'e!e !%'p&, %() %e!(;%e!%! )e &)(# pe,!"# & &,e,!"%
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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-
e!e & "e%
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C1222O11 2O → C512O5 C512O5 %*%"&@ +$#&@ >"#!&@
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%.4. FACTORII CARE INFLUENŢEA!Ă VITE!A DE REACŢIE
V(!e% )e "e%$#e,( "(@ =, >&"'@ $&+%"(!'(@
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Figura 3. (ariaţia constantei Figura !. (ariaţia lgE înitezei de reacţie cu temperatura. funcţie de 1T.
RT
EA$, $, %
−= B7.28)(, %"e "e#$!@ &,>&"' )(%+"%'e( )(, >(+#"% 40 @ logaritmul constantei de
viteză este o funcţie liniară a temperaturii absolute. P%,!% )"ep!e( e!e e+%$@ #;E2303R.
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µπ
σ+σ= T8
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2
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RTEe e
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Figura !1. (ariaţia de energie prin mecanismul stării de tranziţie8 A r -energia medie a reactanţilor9 A p-energia medie a produilor9
A a-energia de actiare a reacţiei directe9 ∆ %!&" ('p&"!%,! =, (,e!(%"e%(,%$( e ,#'e catalizatori. Fe,&'e,#$ =, (,e p&%"!@ ,#'e$e )e cataliză )e $%#?,!#$ +"ee 'atal2sis %"e =,e%',@ )e&'p#,e"e %# )(!"#+e"e !e"'e,%)&p!%! )e *('(!#$ #e)e J%& e"e$(# B1835 pe,!"# "e%&! e"&,%!@ )e&%"ee e"% %%!@ pe &,ep
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p"&p"(e!%!e% %!%$(!(@ ,# =,e',% p%"!((p%"e )("e!@ % %!%$(%!&"#$#( $% "e%e,&'e,e$&" *('(e ,# !"e#(e @#!%!e =, >&"%"% '%!e"(e( ( =, p"&p"(e!@((,)#!%,e$#$ )e %$!e#!%,(@ ,# ,#'%( ?(!e% )e "e%&>&" %# "&' %"e =, %,!(!@%! #&'p#6( *()"&($(( % *()"&*(,&,% %$&&$#$ e,($( 6( '%,(!&$#$ %# # %,($(,@
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p"(, %)%&#$ #,&" %,!(!@&%"!e '(( )e #!%,e$ $#,) =, )(#@"@ %)%& )ee,e"+(e )(, %>%"@ B∆/ i 0. Ce% )e % )% "e%( %!%$(%!@ )e&%"ee%!%$(%!&"#$ %" !"e#( @ >#",(ee e,e"+(e (!e'#$#( ee% e %" )#e $%'&)(>(%"e% % >(e @ "eee e,e"+(e ee% e &,!"%(e p"(,(p(#$#( I %$!e"'&)(,%'(((.
:atalizatorii influenţează cinetica reacţiilor grăbind stabilirea ecilibruluicimic p"(, '&)(>(%"e% 'e%,('#$#( )e "e%
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'#$!e e!%pe (,!e"'e)(%"e >(e%"e )(,!"e e$e ,ee(!,) !"ee"e% #,e( %"(e"ee,e"+e!(e '%( '(( E1 6( E2 % =, >(+#"% 42.
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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p&(($e (%" %!%$(%!&"#$ >%?&"(e%@ ,#'%( #,% )(, %e!e )("e&$&(,) %!%$(%!&"( )(>e"(e"(!e %)%&#"( %e!&,@ %e!%! )ee!($ e!. De %ee% p"&$e'% +@("(( %!%$(%!&"#$#( pe,!"# )(>e"(!e$e "e%e$ =, !('pe "e%
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`9`_A_ )!
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=, %"e ,% &,!%,!@ )e ?(!e@ e ,#'e6!e constantă catalitică %#!%,(e p"(, (&,("(!"('&$e#$%"e BA % '&$e#$e$&" "e%!%,(e%"e "e%!%,!=, p%"!e %# % %!%$(%!&"#$#( # #, "e%!%,! BA → A 6( % p"&)##$#((,!e"'e)(%" >&"'%! # %$! "e%!%,! BA → A .
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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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Re#,&%6!e' =, %e!e p"&ee e(!e,&%"!e '%"e B105 (%" $% $&"#"%"e% 'e!%,#$#( e!e 104 B#,>&!&, !"%,>&"'@ 10 000 '&$e#$e )e C4 =, C3C$. Î, +e,e"%$ =, "e%&!&*('(e e&!e"'e "%,)%'e,!#$ #%,!( e!e >&%"!e '%"e =, !('p e =, "e%&!&*('(e B>&!&$(@ % A+" =, !e*,(% >&!&+"%>(@φ Q 1
− ν−+ → e" "
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'. STAREA COLOIDALĂ A MATERIEI
'.1. DEFINIREA STĂRII COLOIDALE
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'e!%$e$&" e!.C&$&(( de asociaţie
%# &$( liofilimicelari
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:oloizimacromolecula
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'.3. PREPARAREA SISTEMELOR COLOIDALE
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8/20/2019 CURS Chimia Materialelor
148/190
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8/20/2019 CURS Chimia Materialelor
149/190
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'.5. PROPRIETĂŢILE SISTEMELOR COLOIDALE
'.5.1. STAILITATEA COLOI!ILOR
L% p(e")e"e% %pe( p"(, e?%p&"%"e &$(( $(&>($( e !"%,>&"'@ =, geluri>e,&'e, ,#'(! gelifiere sau gelatinizare. C&$&((( %"e "e?(, $% !%"e% )e &$ p"(,%)@#+%"e )e %p@ #,! &$&(( reversibili B+#'% %"%(@. Sep%"%"e% p%"!(#$e$&" &$&()%$e )e 'e)(#$ )(pe"+e,! p"(, =,@$("e %# %)@#+%"e )e e$e!"&$(! e ,#'e6!e
floculare. Î, %#$ #!%,(
"e%)# =, !%"e )e &$ p"(, =,)ep@"!%"e% e$e!"&$(!#$#( &%+#$%,! >&$&(,) )(%$(% e,#'e6!e peptizare. Fe,&'e,#$ p"(, %"e &$#$ p(e")e $(*()#$ )(pe"+e,! )%!&"(!@#,&" !"%,>&"'@"( '%( p"&>#,)e p&%"!@ ,#'e$e )e sinereză B)e ee'p$# ep%"%"e%(%#"!#$#( )e e". S&$(( $(&>&( #,! '%( p#($( p#!,) &%+#$%*(%" # & %,!(!%!e '(@ )e e$e!"&$(!. Ae6!( &$&(( p&! >( !%($(%&"'e%@ p"('#$ !"%! )e (&,( )e%)&"e"(!@ )e
p"('#$ !"%! e$e!"(. A!>e$ >&"'e%@ coloizi pozitivi *()"&((( #,&" 'e!%$e % A$Fe C) C# e!. #,(( &(( % T(O2 CeO2 e!. 6( &$&"%,&"'%&"e@ p"&e )e '(+"%"e % p%"!(#$e$&" &$&()%$e =,!";#, 'p e$e!"(. A!>e$ )%@ e (,!"&)# )&( e$e!"&( =,!";#, &$&()6( e "%&")e%@ $% & #"@ )e #"e,! e$e!"( e &,!%!@ @ p%"!(#$e$e e)ep$%e%@ $% %!&) =, %#$ &$&(($&" p&(!(?( >e,&'e, ,#'(! %!%>&"e@ 6( $%%,&) %,%>&"e@ =, %#$ e$&" ,e+%!(?( BF.F. Re( 1887. P%"!(#$e$e &$&()e =,&,!%! # e$e!"&(( =6( ,e#!"%$(e%@ %"(,($e e$e!"(e 6( &$&()#$ e )ep#,e #
>&"'@ )e >#$+( B floculează. E$e!"&>&"e% e p&%!e >%e %!! pe &$&%,@ ! 6( pe*"!(e.
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8/20/2019 CURS Chimia Materialelor
150/190
P"&!e(,e$e %"e #,! '%"&'&$e#$e >&"'%!e p"(, &,)e,%"e )e%'(,&%(( p"(, %"%!e"#$ $&" %'>&!e" '(+"e%@ p"e %!&) =, 'e)(# %() (%" p"e%,&) =, 'e)(# %(. L% p#,!#$ (&e$e!"( )ep$%%"e% ,# %"e $&. De&%"ee)(?e"e$e p"&!e(,e p"e(,!@ )ep$%@"( e$e!"&>&"e!(e )(>e"(!e $% %e$%6( pe$e!"&>&"e% &,!(!#(e & 'e!&)@ )e ()e,!(>(%"e % %e!&"%.
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P%"!(#$e$e &$&()%$e p"e(,!@ & '(6%"e "e!($(,(e # *('%"e )e%@ %)("e&( )e#"+e '%( "epe)e )e! $% e($(&>($( )%!&"(!@ (,!%($(!@
8/20/2019 CURS Chimia Materialelor
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(. ELECTROCHIMIA. CONVERSIAELECTROCHIMICĂ DE ENERGIE
O"IDARE ŞI REDUCERE
(.1. NOŢIUNI INTRODUCTIVE
G. O!%$) 6(L. V. P ( % " : e ? ( %# (,!e"p"e!%! p"&ee$e )e &()&;"e)#e"e )(, p#,!#$ )e ?e)e"e %$ !e&"(e( e$e!"&,(e. Se ,#'e6!e oxidare, #,
p"&e %"e %"e $& # p(e")e"e %# e)%"e )e e$e!"&,( )e @!"e %!&'( 6( !"ee"e%$&" =, (&,( p&(!(?( M → ,e− M,# Re)#e"e% e!e p"&e#$ )e %ep!%"e )ee$e!"&,( )e @!"e %!&'( M ,e− → M,−. Se =,
8/20/2019 CURS Chimia Materialelor
152/190
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8/20/2019 CURS Chimia Materialelor
153/190
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