Experiment 4

Transcript

EXPERIMENT 4 SOLUBILITY OF IONIC SALTS IN SEAWATER Objectives 1. To st!"#"ise st!"#"ise si$ve# si$ve# !it#te so$%tio! so$%tio! %si!& %si!&  '!o(! c)$o#i"e c)$o#i"e so$%tio!. so$%tio!. *. To "ete#+i!e "ete#+i!e t)e c)$o#i"e c)$o#i"e co!ce!t#t co!ce!t#tio! io! i! se(te# se(te#.. I!t#o"%ctio! P#eci,ittio! Tit#tio!s A tit#tio! ,#ocess t)t is c##ie" o%t s%c) t)t t)e stoic)io+et#ic #ectio! bet(ee! t(o s%bst!ces ,#o"%ces  s$i&)t$- so$%b$e s$t t)t ,#eci,ittes o%t i! t)e so$%tio! is c$$e"  ,#eci,ittio! tit#tio!. A co++o! e+,$e o/  ,#eci,ittio! tit#tio! is ()e! t)e c)$o#i"e io! i!  s+,$e is "ete#+i!e" btit#ti!& it (it)  st!"#" so$%tio! o/ si$ve# !it#te. T)e e0%tio! to s)o( t)e ,#eci,ittio! #ectio! is A&203  C$203 5 A&C$2s3  T)e c)$o#i"e i! t)e s+,$e #ects (it) t)e ""e" si$ve# !it#te ()ic) (i$$ t)e! ,#o"%ce  ()ite ,#eci,itte o/ A&C$ t)t sett$es to t)e botto+ o/ t)e 6s'.  T)e +o%!t o/ si$ve# !it#te #e0%i#e" #e0%i#e" to co+,$ete$- #ect (it) (it) t)e c)$o#i"e c! be c$c%$te" /#i+ co!ce!t#tio! !" vo$%+e %se" to #ec) t)e e!",oi!t. Acco#"i!& to t)e stoic)io+et#ic e0%tio!7 t)e #ectio! bet(ee! t)e t(o is o!e to o!e8 )e!ce t)e +o%!t o/ c)$o#i"e s+,$e e0%$s t)t o/ t)e si$ve# !it#te ""e". E!",oi!ts I! !- tit#tio!7 t)e co+,$etio! o/  #ectio! is o/te! ,)-sic$$- "etecte".  T)is ,oi!t i! t)e tit#tio! is c$$e" t)e e!",oi!t8 ,oi!t ()ic) j%st e!o%&) tit#!t )s bee! ""e". T)e e!",oi!t t)t si&!$s t)e co+,$ete" #ectio! bet(ee! t)e si$ve# io! !" t)e c)$o#i"e c! be s)o(! b- t)e ,#ese!ce o/ i!"icto#. i!"icto#. I! t)is * e,e#i+e!t7 c)#o+te io!7 C#O4  is %se" s t)e i!"icto# i !"icto#.. A so$%tio! o/ c)#o+te * io! is -e$$o( ()i$e t)e ,#eci,itte A& *C#O4  is b$oo"#e". C)#o+te io! is ""e" t t)e be&i!!i!& o/ tit#tio!. P#ese!ce o/ C#O4* i!iti$$- (i$$ t%#! t)e so$%tio! -e$$o(. -e$$o(. U,o! ""itio! o/ st!"#" s$ive# io!7 t)e si$ve# io! (i$$ #ect (it) t)e c)$o#i"e i! t)e s+,$e so$%tio!. W)ite ,#eci,itte o/ si$ve# c)$o#i"e (i$$ /o#+. T)is (i$$ co!ti!%e %!ti$ t)e#e is !o +o#e c)$o#i"e $e/t i! t)e 6s'. Si$ve# io! sti$$ ""e" /te# t)is ,oi!t (i$$ #ect t)e c)#o+te io! i!ste"7 i !ste"7 to ,#o"%ce  ,#eci,itte o/ A&*C#O4 ()ic) is b#ic' #e" i! co$o%#. co$o%#. T)is i!"icte" t)e e!",oi!t /o# t)e tit#tio!. W)t is t)e +i!i+%+ co!ce!t#tio! o/ /#ee si$ve# io! t)t +%st be ,#ese!t i! t)e so$%tio! be/o#e it (i$$ #ect (it) t)e c)#o+te io!9 Let %s ss%+e t)t t)e :C#O4 *; i! t)e so$%tio! is <.<<1 M. t)e! t)e so$%bi$it- ,#o"%ct co!st!t7 = s, s, /o# si$ve# c)#o+te is 1* = s,  > :A& ;*:C#O4*; s, > 1.1*  1< Si!ce :C#O4*; > <.<<1 M7 )e!ce :A& ;* > 1.1*  1< ?7 !" :A& ; > @.@  1<.  T)%s7 o!$- ()e! t)e co!ce!t#tio! o/ si$ve# io! i! t)e so$%tio! ecee"s @.@  1<M7 (i$$ A&*C#O4 ,#eci,itte /o#+. Be$o( t)is co!ce!t#tio! v$%e7 !o si$ve# c)#o+te ,#eci,itte (i$$ /o#+. No( $et %s $oo' t ()t ),,e!s ()e! t)e co!ce!t#tio! o/ c)$o#i"e io! i! s+,$e is <.<1 M !" (e "" si$ve# io! o! it. T)e so$%bi$it- ,#o"%ct t)e! is = s, > 1.  1<1< > :A& ;:C$;7 So t t)e st#t o/ t)e tit#tio!7 :A&;* > 1.  1< 1< D 1  1< * > 1.  1< . T)is is o/ co%#se ve#- +%c) $ess t)! t)e +i!i+%+ co!ce!t#tio! o/ :A& ; bove7 t)t is ()- !o ,#eci,itte o/ A&*C#O4 c! /o#+ t t)e be&i!!i!& o/ t)e tit#tio!. At t)e e0%iv$e!ce ,oi!t7 :A& ; > :C$; !" :A&;* > = s, > 1.  1< 17 :A&; > 1.@@  1<7 ()ic) is sti$$ $o(e# t)! @.@  1<.  T)%s !o ,#eci,itte o/ A&*C#O4 (i$$ /o#+. A/te# t)is e0%iv$e!ce ,oi!t ()e! $$ c)$o#i"e is %se" %,7 ""itio! o/ eve! o!e "#o, o/ si$ve# io! (i$$ i!c#ese t)e co!ce!t#tio! o/ t)e si$ve# &#et$-. At t)is ,oi!t7 t)e so$%bi$it- ,#o"%ct co!st!t o/  si$ve# c)#o+te (i$$ be ecee"e" !" -o% (i$$ see t)e #e" ,#eci,itte "%e to A&*C#O47 si&!$$i!& t)e e!",oi!t o/ t)e tit#tio! is !o( #ec)e". T)is +et)o" is '!o(! s t)e Mo)# +et)o"7  +et)o" /o# "ete#+i!i!& c)$o#i"e i!  s+,$e so$%tio! %si!& c)#o+te io! s t)e i!"icto#. I! t)is e,e#i+e!t7 -o% (i$$ c##- o%t t)e Mo)# +et)o" to "ete#+i!e t)e co!ce!t#tio! o/ t)e c)$o#i"e io! i! t)e se(te#. Be/o#e "oi!& t)e !$-sis7 -o% (i$$ #st st!"#"ise t)e si$ve# !it#te so$%tio! ()ic) is to be %se" i! t)e "ete#+i!tio! o/ c)$o#i"e io! i! t)e s+,$e. P#oce"%#e A. St!"#"istio! o/ t)e si$ve# !it#te so$%tio! 1. Abo%t <.<*< & o/ "#- so"i%+ c)$o#i"e (e#e (ei&)te" cc%#te$-. T#!s/e# 0%!tittive$- i!to  *< +L co!ic$ 6s'. A"" ,,#oi+te$- 1<< +L "isti$$e" (te# to "isso$ve t)e s$t. *. T)e ,G (e#e c)ec'e" %si!&  ,G ,,e#. T)e ,G (e#e "j%ste" to bet(ee!  !" 1< b- ""i!& s%$,)%#ic ci" o# so"i%+ )-"#oi"e i/ !ecess#-. @. 1.< +L o/ H ,otssi%+ c)#o+te i!"icto# (e#e ""e". 4. A < +L b%#ette (e#e c$e!e" t)o#o%&)$- (it) t, (te# !" #i!se  /e( ti+es (it) "isti$$e" (te#. T)e! #i!se !" $$ t)e b%#ette (it) t)e si$ve# !it#te so$%tio! 2,,#oi+te$- <.<1 M3 -o% (is) to st!"#"ise. Tit#te t)e s$t so$%tio! e#$ie# (it) t)e tit#!t %!ti$  ,e#+!e!t o#!&e ,i!' co$o%# is obti!e". . T)is st!"#"istio! ,#ocess (e#e #e,ete" %!ti$ -o% )ve t)#ee v$%es t)t &#ee (it) ec) ot)e#. B. A!$-sis o/ se(te# 1. 1<.< +L ,o#tio! o/ se(te# (e#e +es%#e" cc%#te$-. Fi$te# t)e s+,$e i/  it is c$o%"-. T#!s/e# t)e s+,$e to 1<< +L vo$%+et#ic 6s' !" "i$%te to t)e +#' (it) "isti$$e" (te#. Use  "#o,,e# to(#"s t)e e!" to voi" ecee"i!& t)e $i!e. *. 1<.< +L $i0%ot o/ t)e "i$%te" se(te# s+,$e (e#e ,i,ette" i!to  *< +L co!ic$ 6s'. @. T)e ,G o/ t)e so$%tio! is bet(ee!  !" 1< (e#e e!s%#e" %si!&  ,G ,,e# s bove. 4. 1.< +L o/ H ,otssi%+ c)#o+te (e#e ""e" !" tit#te &i!st t)e st!"#"ise" si$ve# !it#te so$%tio!. . T)e tit#tio! (e#e #e,ete" /o# !ot)e# t)#ee s+,$es.