UNIVERSIDADE FEDERAL DO PARANÁ SETOR DE CIÊNCIAS EXATAS EXATAS DEPARTA DEPARTAMENTO MENTO DE QUÍMICA
CQ050 – FÍSICO-QUÍMICA EXPERIMENTAL I PRÁTICA 6 – ENTALPIA DE FORMAÇÃO DO NH 4C!"# 05$05$%0&5
P'()*+ R,./ M'. Q1,.'(2 3, M,( A1/ L,7. 3" C8" C8" L.9
CURITI:A$PR
Introdução [1]
E", ,;<,'.9,/( ,"= ',7.(/3( 7(9 ,/<. 3, )('9>?( 3, 1/" 7(9<("("+ A ,/<. @ 19 <'(<'.,33, 3, ,"3( ,;,/". ,B <(3, ",' 3,)./.3 7(9( 1/.33, 3, 7(' '(73( /( ".",9 <',""?( 7(/"/,+ C(9( (3 <'(<'.,33, 3, ,"3(B '.>?( 3, ,/<. !H# @ 3.),',/> ,/', ",1" (',"B )./ , ./.7.B 1, "?( (93(" ./3,<,/3,/,9,/, 3( 79./8( <,'7(''.3( <' 78,' @ ,,"+ A <'(<'.,33, ,;,/". 3 ,/<. /(" 3.2 1, ," '/3,2 @ 3,<,/3,/, 3 1/.33, 3, 9@'. 7(/.3 /( ".",9+ P(3,-", ,;<',""' '.>?( 3, ,/<. <, ,1>?( .;(+ HGQ<
!&#
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
Objetivo
D,,'9./' ,;<,'.9,/9,/, ( (' 3 ,/<. 3, )('9>?( 3( 7(',( 3, 9J/.(B 1..2/3( L,. 3, H,""+
Procedimentos Experimentais
C(9( 3,,'9./>?( 3.', 3 ,/<. 3, )('9>?( 3( NH 4C!"# @ ./.=, 3,.3( ,"'11' 3( (''.( ,9 1, ( ,;<,'.9,/( )(. ),.(B )('9 1..23" ',>," ",71/3='." <' (K-+ O" 7('," 3, )('9>?( 3,""" ',>," )('9 <',.9,/, )('/,7.3("B 7(9 ,;7,>?( 3, 3(."B 1, ",'?( 3,,'9./3(" /,", ,;<,'.9,/(+ A" ',>," 3" 1." ",'?( 3,,'9./3(" (" 7('," "?( 3, /,1'.2>?( 3, NH 4OH!# 7(9 HC!# <' )('9' NH4C!# , 3, 3.""(1>?( , 3.""(7.>?( 3, NH 4C!"# ,9 =1 3,".3+ P' ."(B ( ,;<,'.9,/( )(. 3..3.3( ,9 'K" ,<" - Etapa 1: Determinar a constante calorimétrica do calorímetro (C cal ).
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
- Etapa 2: Determinação do calor envolvido na dissolução e dissociação de N !Cl(s).
A1,7,1-", /(9,/, %009L 3, =1 @ 19 ,9<,'1' ./.7. !T .# 3, 5B CB ," )(. 7((73 /( 7('9,'( ,B ,/?( 3.7.(/(1-", 5B4 3, NH4C!"#+ M/,,-", .>?( "1, @ 7(9<, 3.""(1>?( 3( "+ A/((1-", /(9,/, ,9<,'1' !T ) #B 1, )(. 3, 5B C+ A<" ."(B )(. 3,"7'3 "(1>?( , ( 7('9,'( )(. 3(+ - Etapa ": Determinação do calor envolvido na reação entre N !# e Cl.
F('9 3.7.(/3" ( 7('9,'( &00B09L 3 "(1>?( 3, NH 4OH!# , )(. /(3 ,9<,'1' 3, ,1.'.( @'9.7( !T .#B 1, )(. 3, %&B C+ E9 ",1.3 )('9 3.7.(/3" &009L 3 "(1>?( 3, HC!# , )(. /(3 /(9,/, ,9<,'1' !T ) #B &B% C+
Resultados e discussões
- Etapa 1:
D3(" T&G%0B& C T%G6%B C TGB C 9=1G&00 7=1G & 7+-&+ C-&+ P' 771' C7B 1"(1-", ",1./, ,1>?( 9=1+7=1+!T-T&# C7+!T-T&# 9=1+7=1+!T-T%# G 0
!%#
!&00#+!&7+-&+ C-&#+!B C - %0B& C# C7+!B C - %0B& C#
!&00#+!B C - 6%B C# G 0 C7G4%B6 7+ C-& - Etapa 2:
D3(" 9=1G%00 7 =1G & 7+-&+ C-& T.G5B C T) G5B C 9NH4CG5B4 /NH4CG0B&0&9( MMNH4CG5B4&5+9(-& C7G4%B6 7+ C-&+ P' 3,,'9./' ( 7(' 3 ',>?( !Q ' #B )(. 1"3 ",1./, ,1>?(
9=1+7+!T) –T.# C7+!T) –T.# Q' G 0
!#
!%00#+!&7+-&+ C-&#+!5B C - 5B C# !4%B67+ C-&#+!5B C - 5B C# Q' G0 Q' G606B5 7 <' 0B&00 9( 3, NH4C P' 3,,'9./' ( 7(' 3 ',>?( <' & 9( 3, 7(',( 3, 9J/.(B )2,9-", " ',>," ",1.' /NH4CG5B4$5B4&5G0B&00 9(
0B&00 9( – 606B5 7 & 9( – Q' Q' G 60&6B 7+9( -& P""/3(-", ( (' (.3( <' (1, & 7 – 4B& W
5
60&6B 7 - Q' Q' G %5&50B6 W Q' G) HG%5B&506 W+9( -& O 7(' 3, )('9>?( ,/7(/'3( @ <' )('9>?( 3, 7(',( 3, 9J/.( ".3( <'.' 3, ",1" (/"+ E/',/(B ',>?( ),. )(. ./,'"+ P(' .""( ( (' 3 ,/<. 3, 3.""(1>?( 3, NH 4C!"# @ ( 7(' ,/7(/'3(B 7(9 ( "./ ./,'.3(+ P('/( NH4!# C-!#
NH4C!"# H%O!#
) HG - %5B&506 W+9(-&
- Etapa ":
A" 7(/7,/'>," ',." 3(" ',,/," ,"9 3,"7'." ,9 ",1" )'"7(" ,B ",1" ('," "?( 3, CHCG&B5% 9(+L-& CNH4OHG&B60& 9(+L-&
C(9( ,",1.(9,'. 3 ',>?( @ 3, &&B )(. 7713( ( (19, /,7,""='.( 3, 73 "(1>?( <' 1, ( ,;<,'.9,/( )("", ',.23( 7(9 ,",1.(9,'. 7('',+ NH4OH!# HO!# C-!#
CG/+V-&
NH4!# C-!# H%O!#
6
!4#
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–T.# C7+!T) –T.# Q' G 0 !&4#+!&7+-&+C-&#+!&B%C-%&BC# !4%B67+C -&#+!&B% C–%&BC# Q' G 0 Q' G - %%4B 7 <' 0B&5% 9(
C71/3( ( (' <' & 9( -%%4B – 0B&5% 9( Q' – & 9( Q' G - &466B0 7+9( -& C(/,',/3(-", ( (' ,/7(/'3( <' W(1, & 7 – 4B& W - &466B0 7 – Q ' Q' G) HG - 6&B&6 W+9( -& A <'.' 3(" 33(" (.3(" ,;<,'.9,/9,/, , 3(" <',.9,/, (),'3(" <(3,-", (,'B <(' 9,.( 3 L,. 3, H,""B ,/<. 3, )('9>?( !Y ) H# 3( NH4C!"#+ YH$W 9( -& $% H%!# Z N%!#
Z H%!# Z C%!#
HC!# H%O!# NH!# H%O!#
NH!#
- 46B&&
HC!#
- %B&
HO!# C-!#
- 4B0
NH4OH!#
- 0B50
NH4!# C-!#
NH4C!"# H%O!#
HO !# C !# NH4OH!#
%H%!# Z N%!# Z C%!#
NH4 !# C !# H%O!#
NH4C!#
- %5B&5 - 6&B% - 0B%
C(9<'/3( ( (' (.3( 7(9 ( ,"<,'3(B )('/,7.3( <, .,'1' !Y) H G - &4B4 W 9( -&# B ,9-", 19 ,''( 3, E''( ',.( <,'7,/1 G [- &4B4 - !- 0B%#+!- &4B4# -&\]&00^ G 5B04^
Conclusão
A <'.' 3(" ',"13(" (.3("B , 7(9 ( 1;.( 3(" 7(/8,7.9,/(" "(', (" 9,7/."9(" 3 1..2>?( L,. 3, H,""B )(. <("", 7(/71.' 1, 3.""(1>?( 3( 7(',( 3, 9J/.( !NH 4C# @ 19 ',>?( ,;(@'9.7B (/3, 8= .,'>?( 3,
,/,'. / )('9 3, 7('+ A ,/<. 3, )('9>?( !Y ) H# ,/7(/'3 )(. Y ) HG -0B4 W+9( -&B (' 3."7',</, ,9 5B04^ 1/3( 7(9<'3( ( (' ,/7(/'3( / .,'1'+ E", ,''( <("".,9,/, )(. 3,7('',/, 3" <'(;.9>," ),." ( (/( 3( ,;<,'.9,/(B ." 7(9( 7(/".3,'>?( 3, 1, (3 ,/,'. 3,"<',/3.3 3" ',>," )(. '/"9..3 ./,'9,/, (" "(,/," " <'(;.9>," 3, 9""-(19, 7(/".3,'>?( 3, 1, " "(1>," <(""19 3,/".33," .1." 3 =1 " 7.'>," 3(" ,1.<9,/("+ C(/13(B ( ',"13( )(. "/, ".")'.(+
Reer!ncias
& PILLAB L1.2+ F".7(-19.7 ,'9(3./9.7 19.7 , ,1.'.( 19.7(+ %* ,3+ %8<$$___+./3,"+7(9+'$./,'/.(/$_,$$'$.,'+/")$',<(".('``."$<3)a9"3"a)$ b).,$FORMIER^%0&0+<3)
8<$$___+<'(<3+1)1+'$".,"$<'(<3+1)1+'$).,"$c","E"<-H.3'(,/.(-
FISPQ-04604+<3) 4 8<$$___+1/.3(;+7(9+'$".,$.9,"$"('.,"$)."<N.'(,/.(+<3) 5 R+d+B H.3`B F1/39,/(" 3, F".7B 4* E3+B V(+ %+ 6 W+C+B e(2B Q19.7 c,' , R,>," Q19.7"B 6* E3+B V(+ &+ c+B C",/B F1/39,/(" 3, F".7(-Q19.7B A<+ VB <+ 505+
