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Analytical Chemistry LaboratoryBurette Correction

ID Number: 061302856Name: Letitia arah

eat number: 53!rou" B

Date o# $%"eriment: 21 A"ril 2016Instructor: &ro#' (asuyu)i (ama*a

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Objective +o calibrate burette ,hilst ta)in- into consi*eration the room tem"erature an* "ressure

*urin- the e%"eriment

Procedure

1' .ill burette ,ith *istille* ,ater usin- "i"ette/ then ush ,ater s,i#tly to aoi* bubble

#ormation2' easure the em"ty $rlenmeyer as) inclu*in- sto""er4' i"e ,et "art ,ith )im,i"e3' Do not hol* $rlenmeyer as) an* sto""er ,ith bare han*s hol* it ,ith )im,i"e4' A*7ust ,ater in burette until the scale mar) hits 05' A** *istille* ,ater to $rlenmeyer until scale mar) hits 15 cm3'6' easure the mass o# $rlenmeyer as) ,ith sto""er an* *etermine the mass o# *istille*

,ater' 9e"eat "roce*ure 26 #or 5 times8' Chan-e the a**e* ,ater olume to 25 cm3 an* re"eat "roce*ure 26 #or 5 times

Result$%"eriment con*ition:

• 9oom an* ,ater tem"erature: 16'5oC

•

;umi*ity: 88 <• &ressure: 1016'3 h&a

Numb

er

=olum

e

ass o#  

$rlenmeyer as)

> sto""er

 +otal mass ass o# ,ater in

as)

ass o# ,ater

a**e*

1

15 cm3

?'668 -6'62 - 1'?560 - 1'?560 -

2 ?'626 - 2?'?2 - 15'022 -3 ?'55 - '83 - 1'?031 -

?'62 -6'2? - 1'?535 - 1'?535 -

5 ?'6653 - 2?'88?1 - 1'?356 -

 +able 1 ass o# 15 mL o# ,ater

Numb

er

=olum

e

ass o#  

$rlenmeyer as)

> sto""er

 +otal mass ass o# ,ater in

as)

ass o# ,ater

a**e*

1

25 cm3

?'8031 -'263 - 2'?232 - 2'?1?8 -

2 ??'6501 - ?'80 - 2'?238 -3

?'8?0 -'8526 - 2'?61? - 2'?61? -

??'8166 - ?'?232 - 2'?613 -5 ?'8?3 - '8132 - 2'?1?8 - 2'?1?8 -

 +able 2 ass o# 25 mL o# ,ater

Calculation@test is rst *one to *etermine *ata ali*ity #or outliers' +his test coul* be a""lie* by usin-

the #ormula belo,

Q=|suspect value−nearest value|largest value−smallest value

Be#ore "er#ormin- the calculation/ the *ierence bet,een each "oint *ata nee*s to be

assesse*' +his is because outliers ten* to hae the lar-est *ierence bet,een it an* the

measurement nearest to it'

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15 mL ,atermass -4

Dierence-4

1'?031

1'?356 0'0325

1'?535 0'01?1'?560 0'0025

15'022 0'0682 +able 3 ass *ierence bet,een each *ata o# 15 mL mass o# ,ater

.rom the table aboe/ it coul* be seen that the lar-est alue *ierence occurre* bet,een

1'?560 an* 15'022' ;ence/ @test is "er#orme* #or 15'022'

Q=|15.0242−14.9560|15.0242−14.9031

=0.5632

 +he calculate* @ alue is less than the limit o# @ #or 5 sam"les/ ,hich is 0'1' +hus/ the

last *ata in the e%"eriment coul* be re-ar*e* as ?5< reliable'Ne%t/ all the surie* *ata are bein- aera-e*'

 Average mass for 15mL of water=14.9031+14.9356+14.9535+14.9560+15.0242

5=14.9545

 +his aera-e* alue is use* to calibrate the burette as they are not uni#orm an* e%ternal

#actors/ such as tem"erature an* "ressure mi-ht also uctuate the olume o# ,ater *ro""e*

#rom them' +he burette calibration #or 15 mL o# ,ater coul* be calculate* as #ollo,s

 M ' =1000− x (correction value)

 x=(2.294+2.452)

2+0.0034× (20.0−16.5 )+(762.3−760)×0.0013

 x=2.38789

 M ' =1000−2.38789=997.61211g

 +his is the mass o# 1000 mL ,ater at 16'5oC an* 1016'3 h&a 62'2?0 mm;-Ne%t/ the calibrate* olume =4 an* correction alue E =4 #or 15 mL ,ater coul* be

calculate*'

997.61211 (g ) :1000 (mL )=14.9545 (g) :V ' (mL)

V ' =14.9903mL

∆ V =V ' 

−V o=−9.72487×10

−3

mL

Ne%t/ the calibrate* olume =4 an* correction alue E =4 #or 25 mL ,ater coul* be

calculate* usin- the same ste"s as be#ore'@test

25 mL ,atermass *ierence

2'?1?8

2'?1?8 0

2'?238 0'00

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2'?613 0'035

2'?61? 0'0006 +able ass *ierence bet,een each *ata o# 25 mL mass o# ,ater

Because the lar-est *ierence occurre* to be in the mi**le o# the *ata ran-e/ @test coul*

not be "er#orme*' Instea*/ ,e coul* aera-e the *ata'

  Average mass for 25mLof water=

24.9198+24.9198+24.9238+24.9613+24.96195

=24.9373

Ne%t/ the calibrate* olume =4 an* correction alue E =4 #or 25mL ,ater coul* be

calculate*'

997.61211 (g ) :1000 (mL )=24.9373 (g ) :V ' (mL)

V ' =24.9969mL

∆ V =V ' −V o=−3.11018×10

−3mL

.rom both correction alue an* olume/ burette calibration cure coul* be constructe*

0 5 10 15 20 25 30

0'01

0'01

0'01

0'01

0

0

0

Volume (mL)

Correction value (mL)

.i-ure 1 Burrete correction cure #or 15 mL an* 25 mL o# ,ater

 +he rst "art o# the -ra"h 015 mL olume4 has a #unction o#  y=−0.000648325 x  an* the

secon* "art o# the -ra"h 1525 mL olume4 has a #unction o#  y=0.00066147 x

DiscussionCalibration is the "rocess by ,hich a state* measure such as the olume o# a container or

burette is chec)e* #or accuracy' In this e%"eriment/ 25 mL burette is about to be calibrate*'

Burette calibration is necessary because the tem"erature an* "ressure in the laboratory by

the time this e%"eriment ,as "er#orme* *i* not match the stan*ar* tem"erature ,ritten on

the burette' In a**ition/ eery "iece o# olumetric -lass,are has sli-ht ariations'

 +here#ore/ eery "iece o# olumetric -lass,are must be calibrate* in or*er to allo, accurate

measurements'In this e%"eriment/ mass o# 15 mL an* 25 mL o# ,ater ,ere ,ei-he*' .rom the *ata

collecte*/ it coul* be seen that the e%"erimental mass *i* not match the theoretical mass o# 

,ater -ien that ,ater *ensity is 1 -FmL' +here#ore/ the measurements "er#orme* shoul*

hae containe* errors' +hese errors are li)ely to arise #rom ,ei-ht an* olume

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measurement' ;o,eer/ ,ei-ht measurement usin- *i-ital scale is less li)ely to contain

error com"are* to olume measurement usin- burette'A#ter "er#ormin- calculation in the "reious section/ burette correction alues coul* be

obtaine* as #ollo,s

•  ∆ V for15mLis−9.72487×10

−3mL

•  ∆ V for 25mLis−3.11018×10

−3mL

 +hese alues coul* then be use* to construct burette correction cure an* base* on the#unction o# the t,o lines re* an* blue sho,n in "reious section4/ they coul* be use* to

calibrate olume in other e%"eriment'

ReferenceInor-anic an* Analytical Chemistry Laboratory !ui*eIntro*uction to the Analytical Balance an* =olumetric !lass,are' 9etriee* #rom

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