exercise 8 full report

8/9/2019 Exercise 8 Full Report

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Exercise 8

Viscosity of Pure Liquids and Solutions

CHEM 111.1 3L

Distor, edric! ".

#lores $$$, Deo%racias C.

&equiso, Princess '.

Sison, &ic(ard Dean ).

So*era, Eri!a +.

Date Perfor*ed Marc( - and 11, /1-

Date Su0*itted Marc( 18, /1-

Mr. Herin Errol ". Mendo2a

La0oratory $nstructor


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I. Introduction

#luids flo in a *anner in (ic( its co*4onents, (ic( can 0e ato*s or *olecules, sli4 4asteac( ot(er and allo *oe*ent (eneer an adequate s(ear force is a44lied to its total or

4artial *ass. Viscosity, η , is usually defined as t(e ease at (ic( t(e fluid is floin%. +s t(e

*a%nitude of η increases, t(e *ore difficult to flo it is for t(e fluid. $t is also so*eti*es

ter*ed as t(e 5t(ic!ness6 of t(e fluid 7&oussel, /19 t(e (i%(er t(e iscosity, t(e *ore 5t(ic!6 afluid is. #or different fluids, (oeer, t(e ease at (ic( fluids flo is affected 0y certain factorssuc( as te*4erature, t(e inter*olecular forces 4resent on t(e fluid, t(e structure of t(eco*4onents of t(e liquid, for exa*4le, t(e len%t( of t(e *olecules in solution, and t(econcentration, in case t(e fluid is a solution 7:arland, //3. Viscosity is usually ex4ressed in4oise or %;c* s in C:S syste*, or in s;* or !%;* s in S$ units.

Different *et(ods and a44aratuses (ae 0een deelo4ed for t(e quantification and

deter*ination of t(e alue of η for liquids and solutions. + *et(od of *easurin% iscosity is

0y usin% r(eo*eters, (ic( consist of rotatin% concentric cylinders, an inner and outer cylinder,it( t(e torque of t(e inner cylinder o0sered (ile t(e outer cylinder 0ein% rotated 0y a *otor 7+t!ins, //#ens!e, and ?00elo(de isco*eters. $n usin% isco*eters, t(e ti*e of donard flo of a olu*e of a fluid, (ic( is caused *ainly 0y %raitational 4ull is *easuredand t(en calculated usin% t(e *odified and corrected Ha%en>Poiseuille equation

η= Aρt − Bρt 78>1

"(e alue of t(e standard :i00s@ free ener%y, ∆ Ǵ

o

can 0e co*4uted usin% a *odified

Eyrin%@s equation

∆ Ǵ

o= RT ln

ηM

h N A ρ 78>

"(e iscosity of 4oly*er solutions can 0e deter*ined usin% t(e Mar!>Houin! equation

[ η ]=k M a

78>3

(ere [η ] is t(e intrinsic iscosity of t(e solution, and k and a are e*4irical constants

for a %ien 4oly*er>solent syste* at a certain te*4erature.


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"(e o0Aecties of t(e exercise are to 7a deter*ine t(e iscosities of aqueous solutions of *et(anol 7CH3=H and >4ro4anol 77CH3CH=H at arious concentrations9 70 t(et(er*odyna*ic 4ro4erties of t(e *entioned test liquids usin% Eyrin%@s equation, and9 7ccalculate t(e *olecular ei%(t and root>*ean>square end>to>end len%t( of sodiu*car0oxy*et(ylcellulose 7aCMC at different salt concentrations usin% Mar!>Houin!@sequation.

II. Materials and Methods

A. Apparatus and Equipment Cannon>#ens!e and ?00elo(de isco*eters "o4 loadin% 0alance "(er*ostatted ater 0at( Stirrin% rod +s4irator Volu*etric flas!s "i*ers )ea!ers "(er*o*eter Pycno*eter

B. Reagents

Cali0ration liquids ater, et(anol, et(yl acetate "est liquids *et(anol, >4ro4anol Solent /.1/ M and /.//1 M aCl solutions Poly*eric salt sodiu* car0oxy*et(ylcellulose 7aCMC

C. Procedure

#or t(e %eneral 4rocedure of t(e use of Cannon>#ens!e 7and =stald isco*eters, t(eisco*eters ere initially as(ed it( deter%ent and ater, t(en rinsed it( dH= and acetone,and finally rinsed it( t(e sa*4le liquid for analysis. 1/ *L of t(e sa*4le liquid as 4laced intot(e isco*eter, (ic( as equili0rated afterards in t(e t(er*ostatted 0at( of recordedte*4erature. "(ree consecutie flo ti*es it( /.1>second difference ere o0tained, alloin%

*ore trials (eneer it as necessary.

Bit( t(e %eneral 4rocedure, t(e isco*eters ere cali0rated usin% t(e cali0ratin% liquids assa*4le liquids at constant 0at( and roo* te*4erature9 *easured flo ti*es at /, , 3/, 3,-/, -, and / C usin% 4ure test liquid9 and *easured flo ti*es solutions of differentconcentrations. )inary solutions of t(e test liquid and H= ere 4re4ared at concentrations/.1/, /./, /.-/, /.


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III. Results and Discussion

Viscosity, η is a *easure of a resistance to flo of fluid9 *ore s4ecifically it quantifies t(e

resistance t(at a 4ortion of t(e fluid extends to t(e ot(er 4ortions of t(e sa*e fluid. $f to solid4lates are se4arated 0y a t(in fil* of fluid, as s(on 0y t(e fi%ure 0elo, and t(e u44er 4late is

*oed steadily in t(e x>direction it( a %ien elocity,V o , a force ill 0e needed to

oerco*e t(e friction 4resent due to t(e fluid 0eteen t(e 4lates. "(is required force aries for different fluids, elocities, 4late si2es, and t(e distances 0eteen t(e 4lates. )y *easurin% t(e

force 4er unit area of t(e 4late defined as t(e s(ear stress, τ , (oeer, t(e effect of different

4late si2es considered is eli*inated.

#i%ure 8.1. "(e slidin% 4late ex4eri*ent.

+t lo alues ofV o , t(e elocity 4rofile in t(e fluid 0eteen t(e 4lates is linear. $f a 4lot of

τ ersus t(e differential c(an%e in t(e elocity it( res4ect to t(e ertical distance of t(e

4arallel 4lates,dV

dy , co**only called as t(e s(ear rate or elocity %radient, is constructed

for different fluids at constant te*4erature and 4ressure, t(e folloin% fi%ure ould 0e o0sered


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#i%ure 8.3. 7a La*inar and tur0ulent flo.

#luids can 0e %enerally classified as eit(er netonian or non>netonian fluids. etonian

fluids usually ex(i0it la*inar flo at lo elocities. "(e alues of η is constant at certain

te*4eratures and 4ressures and is inde4endent of t(e elocity %radient. So*e exa*4les of netonian fluids include all %ases, all liquids it( si*4le c(e*ical for*ulas, and *ost solutions

of si*4le *olecules. =n t(e ot(er (and, non>netonian fluids (aeη

alues, (ic( are

de4endent on t(e alues of τ , (ic( is defined as t(e force 4arallel to t(e area 0ein%

considered, as o44osed to nor*al forces and stresses t(at acts 4er4endicularly to an area.Co**on ty4es of non>netonian fluids are )in%(a* fluids, (ic( can resist s*all s(ear forcesinfinitely 0ut flo easily under lar%e s(ear stresses. Exa*4les are slurries, Aellies andtoot(4aste. Pseudo4lastics li!e 0lood and ot(er 4oly*er solutions ex(i0it iscosities t(atdecrease it( increasin% elocity %radient. "(ose considered unco**on are dilatants fluids li!estarc( solutions, (ic( (ae alues of iscosity t(at increases as t(e elocity %radient increase.

"(e *et(od used in t(e ex4eri*ent is t(e ca4illary rise *et(od, (ere t(e iscosity of fluids

are deter*ined 0y *easurin% t(e ti*e of flo of a %ien olu*e,V

, of a liquid t(rou%( a

ertical ca4illary tu0e under t(e influence of %raity. Ca4illary isco*eters consist of a ?>s(a4ed%lass tu0e (eld ertically9 in one ar* of t(e ? is a ertical section of 4recise narro 0ore, t(eca4illary. +0oe t(is is a 0ul09 it( it is anot(er 0ul0 loer don on t(e ot(er ar*. "(e liquid isdran into t(e u44er 0ul0 0y suction, and t(en alloed to flo don t(rou%( t(e ca4illary intot(e loer 0ul0. "o *ar!s, one a0oe and one 0elo t(e u44er 0ul0, indicate a !non olu*e.=stald and Cannon>#ens!e isco*eters are so*e a44aratuses t(at *a!e use of t(is idea. +n=stald isco*eter (as a strai%(t tu0e cured at t(e 0otto* 4art and to 0ul0s, (ic( arelocated at t(e u44er and loer ends of t(e tu0e as s(on in t(e folloin% fi%ure


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#i%ure 8.-. +n =stald isco*eter.

)ecause t(e tu0e is strai%(t, t(e flo ti*e of a %ien liquid is lon%er co*4ared to t(at of t(e

Cannon>#ens!e isco*eter, (ic( is also co*4osed of to 0ul0s, 0ut ex(i0its a slanted 4art of t(e tu0e, as s(on 0y t(e fi%ure 0elo.

#i%ure 8.. + Cannon>#ens!e isco*eter.

Measure*ents o0tained usin% an =stald isco*eter is de4endent on t(e olu*e of t(e liquidused 0ecause t(e 4ressure (ead aries it( different solutions. )y usin% t(e Cannon>#ens!eisco*eter, a *odification of t(e =stald isco*eter, *ini*u* c(an%es in t(e 4ressure (eadsince t(e loer 0ul0 is located directly 0elo t(e u44er 0ul0 is 4roduced resultin% to t(e erticalali%n*ent in t(e isco*eter. "(e differences in 4ressure (eads and ot(er in(erent errors, (ic(are *ostly caused 0y t(e %eo*etry of t(e tu0es, are corrected 0y t(e Cannon>#ens!e.

+not(er a44aratus used in t(e ex4eri*ent is t(e sus4ended leel or ?00elo(de isco*eter,(ic( is co*4osed of t(ree tu0es, and 0ul0s located and desi%ned in suc( a ay t(at errorsdue to certain conditions, suc( as t(e 4ressures actin% a0oe, and ot(er in(erent errors arecorrected. "(e liquid initially dran into t(e s*all u44er 0ul0 is not connected to t(e reseroir asit flos don t(e ca4illary durin% *easure*ent. "(e ca4illary is rat(er sus4ended a0oe t(ereseroir. $t (as a t(ird ar* extendin% fro* t(e end of t(e ca4illary and o4en to t(e at*os4(ere,(ic( ensures t(at t(e only 4ressure difference 0eteen t(e to4 of t(e 0ul0 and t(e 0otto* of t(e ca4illary is t(at due to t(e (ydrostatic 4ressure or t(e ei%(t of t(e liquid. "(e 4ressure


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(ead of t(e sus4ended liquid on t(e ca4illary tu0e is inde4endent of t(e liquid ori%inally 4lacedon t(e isco*eter. "(is ty4e of isco*eter is usually used for iscous and 4oly*er solutions7Daniels, Matt(es, Billia*s, )ender G +l0erty, 1


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"(e Ha%en>Poiseuille equation does not consider t(e 4ressure dro4 due to t(e *otion of t(efluid itself9 t(e !inetic ener%y correction are necessary for accuracy. "(e equation s(ould 0ecorrected for tu0e>end effects 0ecause t(e liquid flo could not 0e considered entirely la*inar,0ecause a layer of a liquid is slidin% relatie to one anot(er 0ot( in t(e entrance and exitre%ions, resultin% to eddy for*ations, (ic( i*4lies tur0ulence. $n t(e entrance re%ion of t(e

tu0e, t(e acceleration of t(e fluid decreases t(e alue of

∆ P

9 in t(e exit re%ion, t(e ener%ydue to t(e deceleration of t(e fluid is dissi4ated as (eat. "(e alue of t(e correction factor,

ex4ressed as ρV

8πlt . "o si*4lify calculations, constants A and B are introduced in t(e

equation, reducin% it into t(e folloin% relation

η= A ρt −

Bρ

t 78>8

(ere A is defined as

π r4

gh

8Vl and B as

ρV

8πlt . "(e alues of t(e constants A

and B can 0e calculated usin% t(e infor*ation of t(e di*ensions of t(e isco*eters used,

0ut so*e errors cannot 0e aoided due to so*e irre%ularities suc( as t(e non>unifor*ity of t(eca4illary tu0e. #or furt(er si*4lification of t(e calculations, t(e isco*eters to 0e used s(ould 0e

cali0rated. Constants A

andB

can 0e deter*ined 0y t(e deter*ination of ρ

andt

for liquids it( !non η . )y rearran%in% t(e equation a0oe,

η

ρt

= A− B

t 2

78>

)y 4lottin%η

ρt ersus1

t 2 , a strai%(t line it( a y>interce4t equal to

A and a slo4e

equal to – B

can 0e o0tained, as su%%ested 0y t(e *odified equation. ?sin% t(e liquids

ater, et(yl acetate and et(anol, different alues ere o0tained (ic( ere used for t(ecali0ration of t(e isco*eters. "(e folloin% data ere o0tained for t(e cali0ration of t(eCannon>#ens!e isco*eters, (ic( ere used in t(e ex4eri*ent.

"a0le 8.1. Cali0ration of t(e Cannon>#ens!e isco*eter used for 1>4ro4anol.

Calibrating Liquid Density ρ

!" #g$m%A&erage time o'

'lo( t !" s)iscosity

η!"

cP

Bater .F383 1/.F /.88Et(yl +cetate 88.13 F. /.-3

Et(anol F8.33F F. /.31

Slo4e fro* linear re%ression 7 B , * .8


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y>interce4t fro* linear re%ression 7 A , *;s 1./38-x1/>F

Correlation coefficient 7 r

/.81--4oly*er solution.


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0 0 0 0 0 0 0 0 0 0 0

0

0

0

0.01

0.010.01

0.01

0.01

0.02

0.02

0.02

f(x) = - 4.89x + 0.02R² = 0.82

1/t2 (1/s2)

η/ρt (cm2/s2)

#i%ure 8.8. Cali0ration data for t(e Cannon>#ens!e isco*eter for >4ro4anol and /.//1 MaCl>4oly*er solution.

+fter t(e cali0ration of t(e isco*eters, t(e alues of η of t(e 4ure test liquids *et(anol

and >4ro4anol at different te*4eratures ere deter*ined 0y *easurin% t(e corres4ondin% floti*es for t(e 4articular te*4erature. Viscosities ere co*4uted usin% t(e *odified Ha%en>Poiseuille equation. "(eoretically, as t(e te*4erature of t(e liquid increases, its iscositydecreases. B(en t(e te*4erature is increased, t(e aera%e !inetic ener%y and t(e rando**otion of t(e *olecules are also increased, t(ere0y reducin% t(e ti*e of interaction and t(edistance 0eteen t(e*, reducin% t(e s(ear stresses ex4erienced 0y a stratified layer of *olecules and t(e 0ul! iscosity of t(e fluid 7:arland, i0ler G S(oe*a!er, //3. "(e folloin%

data ere %at(ered for t(e effect of te*4erature on t(e alue of η .

"a0le 8.3. Viscosities of 4ure *et(anol at arious te*4eratures.

*emperature" +Density

ρ!"

#g$m%

A&erage time o' 'lo(

t !" s)iscosity

η!"

#g$m s

3.1 F-.3-


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8.1 /.F81-- 1.3 3.18F8

3/3.1 /.FF


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3.1 F-.3-//.3

-tandard molar enthalpy" ∆ ´ H

o

!" ,$mol /-F


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290 295 300 305 310 315 320 32527.500000

28.000000

28.500000

29.000000

29.500000

30.000000

30.500000

f(x) = 0.06x + 10.65

R² = 1

Temperature, K

ΔG°, J/mol

#i%ure 8.. Plot of ∆ Ǵ

o

ersus te*4erature for 4ure *et(anol.

290 295 300 305 310 315 320 325

76000

7700078000

79000

80000

81000

82000

83000

84000

85000

86000

f(x) = 200.39x + 20472.3

R² = 1

Temperature, K

ΔG, J/mol


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#i%ure 8.1/. Plot of ∆ Ǵ

o

ersus te*4erature for 4ure >4ro4anol.

+not(er condition t(at 4ossi0ly affects t(e alue of iscosity is t(e concentration. $ts effectas tested usin% 0inary solutions of t(e test liquids and ater it( different concentrations. "(e

olu*e of t(e 4ure test liquid needed to 4re4are a olu*e of t(e solution to 0e tested asco*4uted usin% t(e folloin% for*ula

V A

V T =

ρB χ A M A

ρ A M B− ρ A χ A M B+ ρB χ A M A 78>13

(ere χ is t(e *ole fraction of t(e test liquid, + is t(e 4ure test liquid and ) is t(e solent

(ic( is ater in t(is case.

"(e densities of t(e solutions ere calculated usin% t(e *easure*ents o0tained fro* a

4ycno*eter usin% t(e folloin% equation

ρsol=

! "y#+sol−! "y#! "y#+ H

2$−! "y#

% ρ H 2 $ 78>1-

Viscosity alues, t(eoretically, are lar%ely de4endent on t(e nature of t(e 0inary solutionconsidered, t(e inter*olecular forces of attraction, $M#+, 4resent 0eteen t(e solute andsolent 4articles, and t(e *ole fraction of t(e solute in t(e solution, (ic( i*4lies itsconcentration. Stron% $M#+ i*4edes flo and increases t(e iscosity of t(e liquid. $f t(e solute>solute and solent>solent interactions are *ore occurrin% t(an t(e solute>solent interactions,as t(e *ole fraction of t(e solute increases, t(e iscosity decreases. $f solute>solentinteractions are *ore occurrin% t(an t(e solute>solute or solent>solute interactions, as t(e *olefraction decreases, iscosity increases. $t is also found out t(at as t(e iscosity increases, t(e0oilin% 4oint of t(e solution rises, to%et(er it( t(e *olar ent(al4y of a4ori2ation 7Leine,//.

"(e folloin% alues ere o0tained for t(e effect of concentration on t(e iscosity of a liquid.

"a0le 8.F. Viscosities of *et(anol>ater solutions at arious concentrations.

Mole 'raction o'

solute" χ A Density

ρ !" #g$m%A&erage time o'


η!"

#g$m s

/. 81.1-/ .- /.//3-


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Mole 'raction o'

solute" χ A Density

ρ!" g$cm%

A&erage time o'

'lo( t

!" s)iscosity η !"

g$cm s

/. /.


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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

0

100

200

300

400

500

600

700

800

f(x) = - 151.17x + 701.86

R² = 0.4

Mole fraction of solute

η ( /cm s)

#i%ure 8.1. Plot of iscosity ersus concentration of solute of >4ro4anol.

Sodiu* car0oxy*et(ylcellulose, a00reiated aCMC, a 4oly*er it( *any uses in foodsciences, 4(ar*aceuticals, oil>drillin% industry, 4rotein 4urification and *any ot(er industriala44lications, (as t(e folloin% structure

#i%ure 8.13. + sodiu* car0oxy*et(ylcellulose *olecule.

=n t(e ex4eri*ent, t(e 4oly*er as dissoled usin% to different concentrations of t(e solentto inesti%ate on t(e effect of t(e 4oly*er concentration on t(e iscosity of liquids, 4articularly a4oly*er solution9 /.1 and /.//1 M sodiu* c(loride, aCl solution ere used.


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So*e deried iscosity *easure*ents and functions 4resented 0elo can 0e coneniently usedin t(e deter*ination of t(e aera%e *olecular ei%(t and *olecular ei%(t distri0ution of a4oly*er 7CHEM 111 Lecturers and La0oratory $nstructors, /1. Viscosity alues %ieinfor*ation a0out t(e s(a4e and si2e of t(e 4oly*er *olecules.

&elatie iscosity ηrel=

η

ηo=

t

t o 78>1

S4ecific iscosity ηs"=

η−ηoηo

=t −t o

t o 78>11

(ere # is t(e concentration of t(e solution, (ile η , t , andηo ,

t o are t(e

iscosities and flo ti*es for 4oly*er solution and 4ure solent, res4ectiely.

+ 4oly*er is coiled it(out a solent. $n a 4oly*er solution, as t(e concentration increases,t(e iscosity also increases 0ecause *ore 4oly*er c(ains *ean stron%er attraction 0eteen*olecules. :enerally, as t(e concentration of t(e solent increases, t(e iscosity of t(e 4oly*er solution decreases 0ecause t(e solent co*4etes for interaction. +t lo concentrations of t(esolent, solation or dissolution, (ic( is t(e 4rocess of association and attraction 0eteen t(e*olecules of t(e solute and solent, increases. "(is ino!es uncoilin% of t(e 4oly*er, t(ere0yincreasin% t(e iscosity of t(e 4oly*er solution. "(e folloin% ta0ulated alues ere calculatedusin% /.1 M and /.//1 M aCl solent.

"a0le 8.. S4ecific iscosities of aCMC solutions at arious concentrations usin% /.1// MaCl solution as solent.

Concentration g$dL! A&erage 'lo( time" s -peci'ic &iscosity ηs" !

1.// 3.


19/41

"a0le 8.1/. S4ecific iscosities of aCMC solutions at arious concentrations usin% /.//1 MaCl solution as solent.

Concentration g$dL! A&erage 'lo( time" s -peci'ic &iscosity ηs" !

1.// 1.1 /.1


20/41

[ η ]=k ´ M a

78>

)y rearran%in% t(e equation, t(e alue of´ M can 0e calculated as

´ M =( [

η ]k )

1a

78>3

(ere´ M is t(e iscosity aera%e *olecular ei%(t, and k and a are e*4irical

constants t(at can 0e deter*ined ex4eri*entally for a %ien 4oly*er>solent syste* at a certain

te*4erature. S4ecifically, t(e constant a is a function of t(e %eo*etry of t(e 4oly*er

solution. "(e alue of a is /. for ell>connected or ti%(tly curled 4oly*er, (ile for ri%idly

extended 4oly*ers, its alue is 1.F. "(e folloin% ta0le 4resents t(e literature alues for

calculations, calculated alues for t(e iscosity alues to%et(er it( ot(er 4ara*eters and´ M )

"a0le 8.11. Literature alues and constants used for calculations.

-ol&ent$Parameter *+105

dL$g a

/.1// M 1.3 /.1

/./1/ M /.


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A&erage molar mass ´ M

!" g$mol1/181./-1 1/3F1.


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#i%ure 8.1-. Plot for t(e deter*ination of t(e intrinsic iscosity of 1>4ro4anol usin% in(erent andreduced iscosities.

0 0.2 0.4 0.6 0.8 1 1.2

0

1

2

3

4

5

6

f(x) = - 3.59x + 4

R² = 0.89

f(x) = - 3.34x + 5

R² = 0.5

Reduced viscosity

i!e"# (Reduced viscosity)

$!%e#e!t viscosity

i!e"# ($!%e#e!t viscosity)

#i%ure 8.1. Plot for t(e deter*ination of t(e intrinsic iscosity of >4ro4anol usin% in(erent andreduced iscosities.

"(e alues of t(e e*4irical constantsk

and a can 0e deter*ined ex4eri*entally 0y

*odifyin% t(e Mar!>Houin! equation

log [η ]=logk +a log ´ M 78>

)y 4lottin% t(e alues of log [η ] ersus log ´ M and t(rou%( linear re%ression, a line it( a

alue of a slo4e equal toa

and it( y>interce4tlog k

is o0tained.

+fter t(e calculation of t(e intrinsic iscosity, t(e alue of´ M , si2e, radius and len%t( of t(e

4oly*er ere calculated. +ssu*in% t(e 4oly*er s(a4e is s4(erical, t(e radius, r , of t(e

4oly*er is ex4ressed as


23/41

r=(3 M V s"4 π )1

3

78>*ean>square end>to>end len%t(,

⟨r1

2 ⟩ , (ic( ca*e fro* t(e ir!ood>&ise*an t(eory, is calculated as

⟨r

1

2 ⟩=( [ η ] ´ M ∅ )1

3

78>F

(ere∅

is equal to .8-x1/1 dL;*ol c*3, and is called t(e #lory@s constant. "(e folloin%

ere t(e calculated alues for t(e *entioned 4ara*eters.

"a0le 8.1-. Calculated 4ara*eters for aCMC usin% /.1 M aCl as solent.

Parameter /sing inherent &iscosity

η&h !

/sing reduced &iscosity η¿ !

+era%e *olar *ass 7 ´ M ,

%;*ol1/181./-1 1/3F1.*ean>square end to>end

len%t( 7 ⟨r1

2 ⟩ 1.-FF-F88x1/>8 1.8--8-33x1/>8

"a0le 8.1. Calculated 4ara*eters for aCMC usin% /.//1 M aCl as solent.

Parameter /sing inherent &iscosity

η&h !

/sing reduced &iscosity η¿ !

+era%e *olar *ass 7

´ M ,

%;*ol13end -.18//3F3< -.F-188


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len%t( 7 ⟨r1

2 ⟩

#or accuracy of t(e *easure*ents done on t(e ex4eri*ent, certain conditions *ust 0e

satisfied. "(e flo of t(e fluid in t(e isco*eter *ust follo t(at of t(e etonian fluid. "(eliquid *ust 0e 4ure, free of certain i*4urities, (ic( *ay affect t(e flo ti*e t(at it ouldex(i0it. "(e te*4erature of t(e syste* *ust 0e *aintained constant, since t(e iscosity aluesof t(e liquid, or a fluid, in %eneral, is affected 0y te*4erature, as su%%ested 0y t(e exercise.

So*e sources of errors in t(e ex4eri*ent can alter t(e results and reduce t(e accuracy of t(e data o0tained. "(e in(erent assu*4tion of t(e ex4eri*ent t(at t(e flo of t(e liquid in t(eca4illary tu0e is co*4letely la*inar leads to so*e erroneous results. "e*4erature fluctuations,(ic( ere *ini*i2ed 0y t(e t(er*ostatted ater 0at( can 4roduce in eit(er increase or decrease in t(e flo ti*e of t(e fluid in t(e isco*eter, de4endin% on t(e fluctuationsex4erienced. B(en i*4urities are 4resent in t(e tu0es, draina%e clo%%in% occurs and t(e floti*e of t(e fluid is altered. +not(er error t(at affects flo ti*e is t(e tiltin% of t(e isco*eter as

t(e liquid flos9 t(e isco*eter s(ould stand ertically for accurate results. "(e use of ti*erscan also 0e erroneous 0ecause eery indiidual (as different res4onse ti*es for differentinstances. $f t(ere are occurrences of ea4oration of solent or increase in t(e concentration of t(e solution, t(ere are c(an%es in t(e sa*4le co*4osition and t(e corres4ondin% flo ti*es anddensities *easured are also altered. =t(er errors suc( as s4illa%e of sa*4le and not folloin%of 4rocedures are ot(er sources of errors.

I). -ummary and Conclusions

Viscosity is a 4ro4erty of a fluid t(at c(aracteri2es a fluid@s resistance to flo and is affected0y *any conditions. eton@s la of iscosity conce4tuali2es a fluid as 0ein% arran%ed intolayers of 4lanes of *olecules (erein a 4late is !e4t static (ile t(e ot(er 4arallel 4late is*oin% steadily at a certain elocity. "(e *et(od for iscosity deter*ination used in t(eex4eri*ent is t(e ca4illary rise *et(od, (ere t(e iscosity of fluids are deter*ined 0y

*easurin% t(e ti*e of flo of a %ien olu*e, V , of a liquid t(rou%( a ertical ca4illary tu0e

under t(e influence of %raity. "(e flo of t(e liquid in t(e ca4illary is %oerned 0y t(e Ha%en>

Poiseuille equation, (ic( as used entirely in t(e calculations of t(e iscosities and ot(er4ara*eters used in t(e ex4eri*ent. +s t(e te*4erature of t(e liquid increases, its iscositydecreases due to t(e addition of ener%y caused 0y t(e te*4erature rise, oerco*in% t(einter*olecular forces of attraction, (ic( (inders flo and increases iscosity. "(e effect ofconcentration de4ends u4on t(e solation effect of t(e solent in t(e solute. Deried iscosity*easure*ents and functions can 0e coneniently used in t(e deter*ination of t(e aera%e*olecular ei%(t and *olecular ei%(t distri0ution of a 4oly*er. Viscosity alues %ieinfor*ation a0out t(e s(a4e and si2e of t(e 4oly*er *olecules. So*e sources of errors li!e


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in(erent assu*4tions, ex4eri*ental conditions, and syste*atic and rando* in t(e ex4eri*entcan alter t(e results and reduce t(e accuracy of t(e data o0tained.

#or 0etter understandin% of t(e conce4ts, trends and effects of 4ro4erties and conditions, itis reco**ended t(at t(e ex4eri*ent *ay use *ore co*4ounds and solution>solent 4airs.

). -ample Calculations

Calibration o' )iscometer

η

ρt = A−

B

t 2

Calibrating Liquid Density ρ !" #g$m%A&erage time o'


η!"

g$cm s

Bater .F383 1/.F /.88

Et(yl +cetate 88.13 F. /.-3

Et(anol F8.33F F. /.31

)y linear re%ression,


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Slo4e I >.8)Ky>interce4t I 1./38-x1/>F *;s Jalue for +Kr I /.81--


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318.1 .-/-8

33.1 3/.F1FF

)y linear re%ression,

Slo4e I /./


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η&h= 1

1 g

d.

ln 3.65 s

0.75 s

η&h=1.582409d.

g

Calculation o' Intrinsic )iscosity

?sin% t(e alues for reduced iscosities of /.1// M and aCMC solution,

Concentration g$dL! Reduced &iscosity η¿ !

1.// 3.8


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´ M =(5.1588869512.3 +10−5 ) 1

0.91

´ M =103791.6765 g!ol

Calculation o' Molecular Radius

r=(3 M V s"4 π )1

3

r=(3

(103791.6765

g

!ol )(0.565

#!3

g )4 π )1

3

r=24.10131775 #!

r=( 3(103791.6765 g!ol )(0.565 #!3

g )4 π

)1

3

1

(6.02 +10−23 )

r=4.00221 + 1023 #!

!ol

Calculation o' RootMean-quare EndtoEnd Length o' 0aCMC

⟨r1

2 ⟩=

(5.15888695(103791.6765 g!ol )

2.84 +1021 d.!ol#!

3

)

1

3

⟨r1

2 ⟩=1.284484332 +10−6 #!


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)I. Literature Cited

+ndrady, +.L. 7//8. Science and Technology of Polymer Nanofibers. ?S+ 'o(n Biley andSons.

+t!ins, P.B. 7//


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#oust, +.S., Ben2el, L.+., Clu*4, C.B., Maus, L.M. G +ndersen, L.). 718/. Principles of nit!perations, nd edition. Sin%a4ore 'o(n Biley and Sons, $nc.

:arland, C.B., i0ler, '.B. G S(oe*a!er, D.P. 7//3. Experiments in Physical Chemistry , 8t(edition. e or! Mc:ra>Hill.

Leine, $.. 7//. Physical Chemistry , Hill Hi%(er Education.

&o%ers, D.B. /11. Concise Physical Chemistry . e 'ersey 'o(n Biley and Sons.

&oussel, &.M. 7/1. " Life Scientist#s $uide to Physical Chemistry . London Ca*0rid%e?niersity Press.


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exercise 8 full report

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