BKF1243-ANALYTICAL CHEMISTRY 11314.PDF

7/23/2019 BKF1243-ANALYTICAL CHEMISTRY 11314.PDF

http://slidepdf.com/reader/full/bkf1243-analytical-chemistry-11314pdf 1/8

FACULTY OF CHEMICAL NATURAL RESOURCES ENGINEERING

FINAL EXAM INATION

COURSE

ANALYTICAL

C H E MIS T R Y

C O U R S E C O D E

BKF1243

LECTURER

EMAN N.

A L

F A R H A N BI NT I MO H D S A I D

D A T E

8 JA NUA R Y 2014

D U R A T I O N

3 H O UR S

SESSION /SEMESTER

SESSION 2013/2014 SEM EST ER I

PROGRAMME CODE : BKBIBKC BKG

I NS T R UC T I O NS T O C A NDI DA T E :

1

This question paper consists of FOUR 4) questions. Answer ALL questions.

2

All answers to a new question should start on new page.

3

All the calculations and assumptions must be clearly stated.

4

Candidates are not allowed to bring any m aterial other than those allowed by

the invigilator into the ex amination room .

E XA MI NA T I O N R E QUI R E ME NT :

PPENDICES

List of Formulas and Statistic Tables

D O N O T T U R N T H I S P A G E U N T I L Y O U A R E T O L D T O D O S O

This exam ination paper consists of

EIGH T (8)

printed pages including front page.



CONFIDENTIAL

KBIBKC/BKG/13141/BKF1243

QUE S T I ON 1

Industrial pollutant which dum ped into a bo dy of w ater can reduce the dissolved oxygen

concentration and affect the aquatic species One example is at Sungai Gebeng As a

Chem ical Analyst, you are asked to take the reading of dissolved oxygen from the same

location at Sungai Gebeng for 8 days Data is shown in

Table 1

Some Scientists think

that

5 0

ppm of dissolved oxygen level is marginal for fish to live.

Table 1: Daily Dissolved oxygen reading of Sungai Gebeng

D ay

Dissolved 02 (P PM )

4 9

2

5 1

3

5 6

4

4 3

5

4 7

6

4 9

7

4 5

8

5 1

i)

Conduct a statistical test to determine whether the mean dissolved oxygen

concentration is less than 5 0

ppm at the 95 confidence level.

14 Marks)

ii)

Explain the changes that happen if the confidence level is changed to 90 ?

5 Marks)

iii)Determine if the value of

5 6 is an outlier or should be retained at a = 0 0 5

6 M arks)

2



CONFIDENTIAL

KBIBKC BKG 13141JBKF1243

QUES TI ON 2

a)

Titrimetric method based on silver nitrate is sometime called argentometric

method. As a new staff memb er in the Fleischmann s Company, you are asked to

calculate and sketch the titration curve for the titration of 40 m l of 0.04 M NaC l

with 0.05 M A gNO

. To sketch the curve, you should cover three reactions, which

are pre-equivalence, equivalence and post- equivalence.

Given: For AgCl K= 1.82x10°

17 Marks)

b) Calculate the pH of a solution 0.05 M in NaHSO

4

and 0.04 M in Na2SO4.

Given: For

H2SO4,

K

= strong, K

= 1.02 x 102

8 M arks)

QUES TI ON 3

Spectroscopic analytical method is one of analytical methods which are based on

measuring the amount o f radiation produced or absorbed by molecular or atomic species

of interest. The absorbance and concentration relationship should follow B eer s Law.

a)

Identify factors that cause the Bee r s Law relationship to deviate from linearity?

4 M arks)

b)

Express the following absorbance in terms of percent transmittance:

i)

0.494

ii)

0.310

3 M arks)



CONFIDENTIAL

KB/BKC/BKG/13141/BKF1243

c) C onvert the following transmittance data to absorbance:

i)

31.5

ii )

0.103

3 Marks )

d A solution containing

8 75

ppm KMn0

has transmittance of 0.743 in a 1.00 cm

cell at 520

nm. C alculate:

i)

The m olar absorptivity of KMriO4.

5 Marks)

ii )

The ab sorbance of a solution in which the concentration of the complex is

2 50 M.

2 Marks)

iii)

The transmittance of the solutions in ii).

2 M arks)

iv )

The wa ve numbe r of the wave length

520

n m

2 M arks)

v)

The absorbance of a solution that has half of the original transmittance.

1 M ark )

e) Explain which formula expresses the total energy E associated with a molecule.

1 M ark )

Illustrate the energy level diagram in case of absorption and em ission.

2 M ark )

4



191810 3 1 1 3

tm

KB BKC BKG 13141 BKF1243

QUESTION

hromatography analytical method is the most general and common separation

technique, where separation, identification and determination of compound can be done.

a List the main principles of gas chrom atography.

1 M a r k)

b Explain how the chrom atography is considered one of the separation techniques

in analytical chemistry.

1 M a r k)

c Illustrate a simple diagram showing the interaction between stationary and mobile

phases.

5 M a rk s)

d Explain how do the Gas Liquid Chrom atography and Gas Solid Chrom atography

differ?

2 M a rk s)

e Illustrate the three main parts in gas chrom atography.

3 M a rk s)

The chromatogram of two substances A and B show ed retention time of 13.20 and

14 65

mm , respectively, on a 30 cm column. The peak width of A and B are 1.03

and 1.25 m m, respectively. Calculate:

i

he column reso lution.

2 Ma rk s)

5



CONFIDENTIAL

KBIBKC BKG 13141 BKF1243

ii he average number of plates in the column.

3 Marks)

iii

he plate height.

2 Marks)

iv

he length of column required to achieve a resolution of 1.5.

3 Marks)

V

he t ime required to elute substance B on the column that gives

value

of

1 5 and how long the colum n should be for good resolution?

3 Marks)

END OF Q UESTION PAPER



CONFIDENTIAL

KB BKCIBKG 13141 BKF1243

APPENDICES

Appendix

Table 2: Values oft

or

various level of probability

.Dcgres of

Fr doni do

Pro bf f l i i / kvth

0.10

.0 5

0.01

D c g m s o f

Freedom NJ

I

ro bnbiIi j

l v l s

0.10

05

1

6.31

12.71

16

1.75

112

2.92

2

2.92 4 3

9.92

17

1,74

2.11

2.90

3

2.35

3.18

5.84

18

73

2.10

2.88

4

2.13

2.78

-1.60

19

1.73

109 2,86

5

101

2.57

4.03

20

1.72

2.09 2.85

6

1.94

2.45 3.71

22

72

2.07 2,82

7

1.81

2.36

.i. 50

24

1.71

2.06 2.80

S 1.86

2.31

3.36

26

1.71

2.06

2.78

9

1.83

2.26

3.25

28

1 70

2.05 2.76

10

1.81

2.23

3.17

30

1.70

2.04 2.75

11

1.80

2.20

3

1.68 2.02 2.70

12

s 2. 18

3. 06

60

67

2.00

2.66

13

.77

2.16 3.01

90

1.66 1.98 162

14 1.76

2.14

3 00

120

1.66

1.98 2.62

15

1.75 2.13

2.95

1.65

1.96

2.58

Table 3: Critical values for Q test

0.941

0.970

0.994

4 0.765

0.829

0.926

0.642

0.710

0.821

6

0.560 0.625

0.740

7

0.507 0.568

0.680

8

0.468

0,526

0.634

9

0.437

0.493

0,598

10

0.412

0.466

0.568



CONFIDENTIAL

KBIBKCIBKG/131411BXF1243

Appendix B

A =— ogT

=-1og-

og --=abC

sbC

hv

=1=hc

R

2AZ

2

[ t

R)B

(tR)A]

W

+W

A+WB

Z

=

X

1 -

tR

^ N

tM

t

x

t

fl B - tM

(t

R A 1M

tR)I =

R8 )

5,/ 2

tR)2

R 5 )

N6

R5)1j7

p_

R )

j7

x

N

=

N

=1111

N— i

l

=

x

±zc

o-

/- X+

-

8

Documents

BKF1243-ANALYTICAL CHEMISTRY 11314.PDF