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RESULT:

-e'i)(e on ignition for 'ample % i' fo(n) to *e = 0.9

-e'i)(e on ignition for 'ample & i' fo(n) to *e = 0.594

OBJECT:

c) TO CHECK FATTY ACI& AN& ESTERS IN GIVEN SAMPLES

APPARATUS:

&(rette

onical fla'k

&eaker

Pipette

C!EMICALS:

0.5 / /a

0.5 /

OBSERVATIOS:

INITIAL REA&ING(*) FINAL REA&ING(*) &IFFERENCE(*)

FOR BLA" READI#

0.0 0." 0."

0." 0.12 0."FOR SAMPLE A

Alishba Sana M.Sc (Final) Seat # H0401008

FOR SAMPLE A FOR SAMPLE +

Wt of empty china )i'h ".30 gm ".31 gm

Wt of china )i'h+glycerin "!.39 gm "!.3" gm

Wt of glycerin 5.09 gm 5.05 gm

Wt of china)i'h+glycerinafter ignition

".32 gm ".34 gm

Wt of glycerin lo'' 0.02 gm 0.0 gm

%Residue=

100xsampleofwt

losswt

0.02 100 5.09

0.9

0.0 100 5.05

0.594

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0.12 0.19 0.3

0.19 0.!9 0.3

FOR SAMPLE B

0.!9 1.9 0.51.9 1.!9 0.5

Alishba Sana M.Sc (Final) Seat # H0401008

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+ee,La%e" La-

&eer6am*ert aw, more commonly known a' &eer7' aw, 'tate' that the opticala*'or*ance of a chromophore in a tran'parent 'ol$ent $arie' linearly with *oth the 'ample

cell pathlength an) the chromophore concentration. &eer7' aw i' the 'imple 'ol(tion to

the more general )e'cription of 8awell7' far6fiel) e(ation' )e'cri*ing the interaction oflight with matter. :n practice, &eer7' aw i' acc(rate eno(gh for a range of chromophore',

'ol$ent' an) concentration', an) i' a wi)ely ('e) relation'hip in (antitati$e

'pectro'copy.

%*'or*ance i' mea'(re) in a 'pectrophotometer*y pa''ing a collimate) *eam of light at

wa$elength ; thro(gh a plane parallel 'la* of material that i' normal to the *eam.

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8any factor' can affect the $ali)ity of &eer7' aw. :t i' ('(al to check for the linearity of

&eer7' aw for a chromophore *y mea'(ring the a*'or*ance of a 'erie' of 'tan)ar)'.

Thi' Acali*rationA can al'o remo$e error' in the eperiment, the e(ipment, an) the

*atch of reagent' '(ch a' c($ette' of (nknown pathlength

+a.ic Pi/cip*e. f Spec"p1"e"

% 'pectrophotometer con'i't' of two in'tr(ment', namely

%spectrometerfor pro)(cing light of any 'electe) color wa$elength.

% photometerfor mea'(ring the inten'ity of light. The in'tr(ment' are arrange)

'o that li(i) in a c($ette can *e place) *etween the 'pectrometer *eam an) the

photometer. The amo(nt of light pa''ing thro(gh the t(*e i' mea'(re) *y thephotometer. The photometer )eli$er' a $oltage 'ignal to a )i'play )e$ice,

normally a gal$anometer. The 'ignal change' a' the amo(nt of light a*'or*e) *ythe li(i) change'.

D$t$r%i&'ti(& () C(&*$&tr'ti(&

:f )e$elopment of color i' linke) to the concentration of a '(*'tance in 'ol(tion then that

concentration can *e mea'(re) *y )etermining the etent of a*'orption of light at theappropriate wa$elength.

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#pectrophotometry in$ol$e' the ('e of a 'pectrophotometer. % 'pectrophotometer i' a

photometer a )e$ice for mea'(ring light inten'ity that can mea'(re inten'ity a' a

f(nction of the color, or more 'pecifically, the wa$elength of light. There are many kin)'of 'pectrophotometer'. %mong the mo't important )i'tinction' ('e) to cla''ify them are

the wa$elength' they work with, the mea'(rement techni(e' they ('e, how they ac(ire

a 'pectr(m, an) the 'o(rce' of inten'ity $ariation they are )e'igne) to mea'(re. therimportant feat(re' of 'pectrophotometer' incl()e the 'pectral *an)wi)th an) linear range.

The 'pectrophotometer mea'(re' (antitati$ely the fraction of light that pa''e' thro(gh agi$en 'ol(tion. :n a 'pectrophotometer, a light from the lamp i' g(i)e) thro(gh a

monochromator, which pick' light of one partic(lar wa$elength o(t of the contin(o(''pectr(m. Thi' light pa''e' thro(gh the 'ample that i' *eing mea'(re). %fter the 'ample,

theinten'ityof the remaining light i' mea'(re) with aphoto)io)eor other light 'en'or,

an) the tran'mittancefor thi' wa$elength i' then calc(late).

Se23e/ce f e!e/".

:n 'hort, the 'e(ence of e$ent' in a 'pectrophotometer i' a' follow'>

1. The light 'o(rce 'hine' thro(gh the 'ample.2. The 'ample a*'or*' light.

. The )etector )etect' how m(ch light the 'ample ha' a*'or*e).

4. The )etector then con$ert' how m(ch light the 'ample a*'or*e) into a n(m*er.5. The n(m*er' are either plotte) 'traight away, or are tran'mitte) to a comp(ter to

*e f(rther manip(late) e.g. c(r$e 'moothing, *a'eline correction

Alishba Sana M.Sc (Final) Seat # H0401008

http://en.wikipedia.org/wiki/Photometerhttp://en.wikipedia.org/wiki/Intensityhttp://en.wikipedia.org/wiki/Photodiodehttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Transmittancehttp://en.wikipedia.org/wiki/Photometerhttp://en.wikipedia.org/wiki/Intensityhttp://en.wikipedia.org/wiki/Photodiodehttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Transmittance

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Spectrpht!etric cells

ell' or c($ette' are '(pplie) with $arying light path' an) )ifferent (alitie' of

gla''. 8o't 'pectrophotometric work i' con)(cte) with 'tan)ar) rectang(lar cell' of 1

cm path length. The'e are '(are in cro''6'ection an) a*o(t 4 time' a' high a' they arewi)e. They generally ha$e a pathlength tolerance of 60.01 mm. :n a))ition, rectang(lar

cell' of 0.1, 0.5 an) 4 cm are commercially a$aila*le.