UNIVERSIDAD CENTRAL DEL ECUADOR FACULTAD DE CIENCIAS QUÍMICAS BIOQUIMICA CLINICA QUIMICA ANALITICA CUANTITATIVA II
TEMA: METODO DE LIEBIG-DENIGES: DETERMINACION DE IONES
CIANURO CON UNA SOLUCION DE NITRATO DE PLATA
Autores: María Caro!"a Cr!#$" D!e%o Lasso Este&a"ía R!'era María Fer"a"(a )*+!%a
,./-,./
RESUMEN
E" a 0rese"te !"'est!%a1!$" 2!2!o%r3&!1a se e40o"e" e &u"(a5e"to 6 os 0r!"1!0!os so2re u"o (e os 57to(os 1o50e8o 57tr!1os 0ara !(e"t!&!1a1!$" (e !o"es9 La &or5a1!$" (e 1o50e8os e" sou1!$" re0rese"ta u" 0a0e !50orta"te e" 5u1os 0ro1e(!5!e"tos a"aít!1os; es 0os!2e (eter5!"ar 5u1os !o"es 5et3!1os; t!tu3"(oos 1o" u" rea1t!'o a1o50e8a"te9 E 57to(o (e L!e2!% se 2asa e" a 'aora1!$" (e !o" 1!a"uro 1o" "!trato (e 0ata; &or53"(ose u" 1o50e8o 5u6 esta2e; a a 5í"!5a 1a"t!(a( (e e41eso (e rea1t!'o se '!sua!#a a 0rese"1!a (e u"a tur2!(e# 0er5a"e"te; 0re1!0!ta(o
I" te 0rese"t 2!2!o%ra0!1a resear1 0rese"ts te 2a1=%rou"( a"( te 0r!"1!0es o" o"e o& te 1o50e4o5etr!1 5eto(s &or !(e"t!&6!"% !o"s are e40ose(9 Te &or5at!o" o& 1o50e4es !" sout!o" re0rese"ts a" !50orta"t roe !" 5a"6 a"a6t!1a 0ro1e(ures; !t !s 0oss!2e to (eter5!"e 5a"6 5eta !o"s; !(e"t!&6!"% >!t a rea%e"t9 Te L!e2!% 5eto( !s 2ase( o" te 'auat!o" o& te 16a"!(e !o" >!t s!'er "!trate; &or5!"% a 'er6 sta2e 1o50e4; to te 5!"!5u5 a5ou"t o& rea%e"t !s (!s0a6e( te 0rese"1e o& a 0er5a"e"t tur2!(!t6; 0re1!0!tate tat !s 0ro(u1e( 26 te &or5at!o" o& te 1o50e4 o& s!'er 16a"!(e9 I" te 5eto( o& L!e2!%-De"!%es aso use( as a" !"(!1ator to te 0otass!u5 !o(!(e; at (!sso1!ate !o(!(e !o" 0re1!0!tates >!t te e41ess o& !o" s!'er tat !s use( as a" !"(!1ator to !(e"t!&6 te 0o!"t estea6 6ou 1a" (eter5!"e te 1o"1e"trat!o" or a5ou"t o& 16a"!(e 0rese"t !" a sa50e 0ro2e59 Keywords: 1o50e4;
5eto(; e41ess9
OBJETIVOS
%UN&AMENTO TEORICO:
Geeral
E4!ste" 'ar!os 57to(os ut!!#a(os e" a !(e"t!&!1a1!$" (e 1!a"uro !2re; e"te"(!7"(ose 1o5o ta a 1!a"uro (!so1!a(o e" sou1!$"; %e"era5e"te 0ara ase%urar esto se tra2a8a 1o" u" 0? 2asta"te a1a!"o @0?.-. 0ara e'!tar a 0rese"1!a (e ?CN9 E 57to(o (e L!e2!% es u" 57to(o (e 'aora1!$" (!re1ta (e !o"es CN; e" e 1ua se e50ea e A%NO 1o5o t!tua"te; (!1o 57to(o 1o"st!tu6e u" e8e50o (e 0ro1e(!5!e"to (e (ete11!$" (e 0u"to &!"a
De&!"!r e &u"(a5e"to (e 57to(o (e L!e2!%-De"!%es 0ara a (eter5!"a1!$" (e !o"es 1!a"uro Es!ec"#$cos
I"'est!%ar os 0r!"1!0!os (e 57to(o L!e2!%-De"!%es e" a 2!2!o%ra&ía Co"o1er e 0ro1e(!5!e"to (e 57to(o (e L!e2!%-De"!%es 0ara rea!#ar e a"3!s!s res0e1t!'o
&ase so!(a 1o"sta"te9 Cua"(o se a(!1!o"a sou1!$" (e A%NO so2re u"a sou1!$" (e u" 1!a"uro se &or5a u" 1o50e8o ata5e"te esta2e e !"1ooro:
6 sus !o"es e" sou1!$" es 1ara1ter!#a(o 0or su 0s:
−¿ ¿ +¿+ CN −¿ ¿ −¿ ⇌ Ag ( CN ) +¿ + 2 CN ¿ 2
Ag
AgC N ( s) ⇌ Ag
¿
¿
+¿
Ag
¿
¿ −¿
2 −¿
¿
CN ¿
¿ K ps=¿
Ag ( CN )
¿ +¿
¿
Ag
¿ −¿
¿
CN
E" e 57to(o (e L!e2!%-De"!%es se e"1ue"tra e uso (e I 1o5o !"(!1a(or 0ara 0o(er o2ser'ar e 0u"to &!"a (e a 'aora1!$"9
¿ ¿2 ¿ ¿ ¿ K f =¿
U"a 'e#
2
−¿ ⇌ 2 Ag C N ( s) +¿+ Ag (CN )¿ Ag
Este 57to(o (a 1o5o resuta(o a &or5a1!$" (e (os 1o50e8os a"tes 5e"1!o"a(os9 Se !"!1!a a 'aora1!$" a+a(!e"(o A%NO se &or5ar3" e" u" 0r!5er 5o5e"to !o"es (!1!a"oar%e"tato9 E 0u"to (e e
¿
−¿ ⇆ ↓ AgI +¿+ I ¿ La a0ar!1!$" (e u" 0re1!0!ta(o 2a"1o (e 1!a"uro (e 0ata es usa(a 1o5o 0& e" a t!tua1!$" (e L!e2!%9 E e
Ag
¿
E" este 1aso; as 5oes (e A% a+a(!(as asta e 0u"to (e e
@Ca2rera; ,H METODO Para a (eter5!"a1!$" (e a 1a"t!(a( (e 1!a"uros 0rese"tes e" u"a sou1!$" se 1o5!e"#a 1o" u"a sou1!$" 0atr$" (e 1o"1e"tra1!$" 1o"o1!(a (e "!trato (e 0ata 6 6o(uro (e 0otas!o 0ara
CONC'USIONES
Se (eter5!"$
Barreto; C9 @Ju!o (e ,..9 UNAC. O2te"!(o (e tt0:KK>>>9u"a19e(u90eK(o1u5e "tosKor%a"!#a1!o"K'r!K1(1!traKI"& or5esF!"aesI"'est!%a1!o"KJu !o,..KIFBARRETOPIOFI ARNKCAP9,I9PDF
Ca2rera; N9 R9 @,H9 Fundamentos de química analítica básica. Análisis cuantitativo. Coo52!a :
E(!tor!a U"!'ersa (e Ca(as 9 Dou%as A9 S=oo%; D9 M9 @./9 Introduccin a la química analítica. Ca!&or"!a9
Ae(os
Ae(o ): E*erc$c$o del +,-odo de '$eb$.
U"a 5uestra (e a%ua se a"a!#$ 0or 1o"ta5!"a1!$" 1o" 1!a"uros; 0ara o 1ua se to5$ u"a aí1uota (e .9 5; a 1ua se 'aor$ 1o" ,95 (e A%NO 9.N asta a0re1!ar su tur2!(e#9 Deter5!"ar os %KL (e NaCN e" e a%ua9 g / L NaCN =
V AgNO 3 N AgNO 3∗0.098 g / meq Vali ( L)
L∗0.100 meq ∗0.098 g L 0.025 meq g / L NaCN = 0.1 L
g / L NaCN =¿
9,
Ae(o /: E*erc$c$os Ad$c$oales )0
Ca1ua a sou2!!(a( e" % (e Ba@IO, 0or 1a(a 5 (e sou1!$"9 0s Ba@IO, /; . -. Ba @IO,
Ba ,IO S
0s Ba@IO, S@,S , 0s Ba@IO, S S
S
√ 3
√ 3
K ps 4
−10
6,5 · 10 4
,S
S 9/9. -M S 9/9. -
mol ∗487.1323 g L ∗0.5 L 1 mol Ba ( IO 3) 2
S 9., %
,9 Cu3 es a 1o"1e"tra1!$" (e !o"es !(ro"!o e" , 5 (e a%ua (est!a(a ?,O?,O ?OO? ?O O? .9.-. ?O O? ?O , ?O √ K W ?O √ 1.10
−14
−7
1.10
?O −7
? O
1.10
?O
mol ∗0.250 l L −8
2,5.10
9 Ca1ue e &a1tor %ra'!57tr!1o e" a (eter5!"a1!$" (e Fe; e" a
PM o Pat sustanciabuscada PM sustancia pesada
e 2 ( !O 4 ) 3 FG e 2 O 3
FG
399,88 g / mol 159,69 g / mol
FG ,9