chem lab 3 unit 2

7/23/2019 Chem lab 3 unit 2

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WATER OF CRYSTILLIZATION

Title/Date: Water of Crystallization, 9/!/"#

Purpose:To $n% t&e n'()er of (ole*'les of +ater of *rystallization resent in

iron-II. s'lfate -FeSO012O.

Background Information: T&e stron3 %iole of +ater (a4es it an e1*ellent sol5ent

for t&e ions of ioni* soli%s s'*& as salts an% )ases0 6any ioni* *o(o'n%s, +&en

*rystallize% fro( +ater sol'tion, ta4e ' %e$nite roortions of +ater as an inte3ral

art of t&eir *rystal str'*t'res0 It also *a'ses +ater (ole*'les to atta*& t&e(sel5es

to ions in sol'tion0 S'*& ions in sol'tion are *alle% &y%rate% ions0 W&en so(e

sol'tions of &y%rate% ions are e5aorate%, t&e soli% salt *rystallizes fro( t&e

sol'tion an% a $1e% n'()er of +ater (ole*'les are in*ororate% into t&e *rystal

str'*t're0 T&ese n'()er of (ole*'les are *alle% +ater of &y%ration or +ater of

*rystallization0 T&is +ater of *rystallization (ay )e %ri5en o7 )y t&e ali*ation of

&eat0 Sin*e t&e la+ of %e$nite *o(osition &ol%s for *rystalline &y%rates, t&e

for('la of t&e an&y%ro's *o(o'n% is 4no+n, yo' *an t&en %eter(ine t&e for('la

of t&e &y%rate0

List of Materials and Apparatus:

8'rette,

Cla( stan%

iette

iette $ller

A*i%i$e% a'eo's otassi'( (an3anate -;II. -


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Procedure:

T&e )'rette +as $lle% +it& FA#0T+enty $5e *(#FA +as iette% into a *oni*al =as4

an% a (eas'rin3 *ylin%er +as 'se% to a%% aro1i(ately ! *( #of FA 0 T&is

sol'tion +as titrate% +it& FA # fro( t&e )'rette 'ntil t&e $rst er(anent in4 *olor

re(aine% in t&e sol'tion0 S'>*ient f'rt&er titrations +ere erfor(e% to o)tain

a**'rate res'lts0 T&e titration res'lts +ere re*or%e% in a %ata ta)le0

Precautions:

"0 Ens're t&at all rea%in3s are ta4en at eye le5el0

0 Re(o5e any +ater )'))les fro( t&e li'i% $rst an% t&en re(o5e any %rolets

of insi%e or o'tsi%e of t&e *ontainer0

#0 Ens're t&at no (o5e(ent is %one +&ile re*or%in3 t&e (ass of t&e se*i(en0

0 Ens're t&at ALL la)oratory 3lass+are is *leane% )efore 'sin30

?0 Ens're t&at +&en ta4in3 e1a*t 5al'es -e030 ? *(# 2Cl. t&e )otto( of t&e

(enis*'s to'*&es t&e (ar40

Data Table:

Trial " Trial Trial # Trial Trial ? Trial @Initialrea%in3/(l

09 09 09 0!" 0!" 099

Finalrea%in3/(l

@0#9 @0B9 @0#9 @0 ?0B B099

Titre/(l 0"! 0"! 0"! 0" #0 0 !!A5era3e 5ol'(e of FA#: 0"@ *(#

Calculations:

? Fe-a. B2-a. 6nOD-a.?Fe#-a. 6n-a. 2O-l.

Na(e: S&el%on 6iller


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6ole ratio of Fe : 6nO is ?:"

of (oles of


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T&erefore t&e er*enta3e aarat's error -!0#!/0"@.G "!! "0

T&e er*enta3e error in *al*'latin3 t&e N'()er of (oles in 2O --BD./ .G"!!

"09

Discussion: 8e*a'se of t&e lo+ er*enta3e error -"09. in t&e *al*'lation of t&e

n'()er of (oles of +ater in FeSO012O, it is safe to say t&at t&e res'lts o)taine%

+ere relia)le0 T&e er*enta3e error in ta4in3 rea%in3s fro( t&e )'rette +as fo'n% to

)e "00 T&is ro*e%'re 'se% to %eter(ine t&e n'()er of (oles of +ater in

FeSO012O *o'l% ro%'*e (ore a**'rate res'lts if (ore trials +ere %one, ta4in3 a

(ore a**'rate a5era3e0 6ore a**'rate instr'(ents *o'l% also )e 'se% in or%er to

o)tain )etter res'lts0

Conclusion: T&e *al*'late% n'()er of (oles in +ater in FeSO012O is B (oles0

Na(e: S&el%on 6iller

chem lab 3 unit 2

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