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2216(a)

THE UNIVERSITY OF SYDNEY CHEM1611 - CHEMISTRY 1A (PHARMACY) FIRST SEMESTER EXAMINATION

CONFIDENTIAL JUNE 2012

TIME ALLOWED: THREE HOURS

GIVE THE FOLLOWING INFORMATION IN BLOCK LETTERS SID FAMILY NAME NUMBER TABLE OTHER NAMES NUMBER OFFICIAL USE ONLY  All questions are to be attempted. There are 19 pages of examinable material.  Complete the examination paper in INK.  Read each question carefully. Report the appropriate answer and show all relevant working in the space provided.  The total score for this paper is 100. The possible score per page is shown in the adjacent tables.  Each new short answer question begins with a .  Only non-programmable, Universityapproved calculators may be used.  Students are warned that credit may not be given, even for a correct answer, where there is insufficient evidence of the working required to obtain the solution.  Numerical values required for any question, standard electrode reduction potentials, a Periodic Table and some useful formulas may be found on the separate data sheets.  Pages 14, 16, 22 and 24 are for rough work only.

Multiple choice section Marks Pages

Max

2-9

30

Gained

Short answer section Marks Page

Max

10

5

11

7

12

7

13

4

15

11

17

7

18

7

19

7

20

6

21

4

23

5

Total

70

Check Total

Gained

Marker

CHEM1611 

2012-J-2

2216(a)

11

C is used in positron emission tomography – PET. It is synthesised by bombarding a N target with protons. Write a nuclear equation for the formation of 11C and thus identify the by-product of this synthesis. 14

Marks

2

11 C undergoes positron decay with a half life of 20.3 minutes. Write a nuclear equation to identify the product of this decay reaction.

 Calculate the wavelength of light (in nm) emitted when an electron moves from the n = 4 to n = 2 energy levels in a hydrogen atom.

Answer: What is the energy of this radiation (in kJ mol–1)?

Answer:

Page Total:

3

CHEM1611

2012-J-3

2216(a)

 Draw the Lewis structure of carbon dioxide and label the electron pairs as either ‘-bond’ or ‘π-bond’ or ‘lone pair’.

Marks

4

What is the hybridisation of the carbon atom and the oxygen atoms? C:

O:

Does carbon dioxide have a permanent dipole moment? Explain your reasoning.

 In a standard acid-base titration, 25.00 mL of 0.1043 M NaOH solution was found to react exactly with 28.45 mL of an HCl solution of unknown concentration. What is the pH of the unknown HCl solution at 25 C?

pH = Page Total:

3

CHEM1611

2012-J-4

2216(a)

 Complete the following table, include resonance structures if appropriate. The central atom is underlined. Formula

PCl5

SOCl2

HCOO–

Lewis structure

Arrangement of electron pairs around the underlined atom Molecular geometry Intermolecular forces present THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

Page Total:

Marks

7

CHEM1611

2012-J-5

2216(a) Marks

 Sketch the shape of a 3px orbital.

4 z

x

y

Sketch the radial probability (ψ2) of an electron in a 3px orbital.

distance f rom nucleus Sketch the shape of the  orbital formed by overlap of a 3px orbital and an s orbital. Clearly show the position of the two nuclei.

Page Total:

CHEM1611

2012-J-6

2216(a)

 Complete the following table. Make sure you complete the name of the starting material where indicated. STARTING MATERIAL

REAGENTS/ CONDITIONS

CONSTITUTIONAL FORMULA(S) OF MAJOR ORGANIC PRODUCT(S)

HBr / CCl4 (solvent)

1. Mg / dry ether 2. CO2

Name:

O

excess (CH3)2NH Cl

O O

3 M NaOH

Name:

Page Total:

Marks

11

CHEM1611

2012-J-7

2216(a)

 Methylphenidate, also known as Ritalin, is a psychostimulant drug approved for treatment of attention-deficit disorder. It belongs to the piperidine class of compounds and increases the levels of dopamine and norepinephrine in the brain through reuptake inhibition of the monoamine transporter.

methylphenidate CO2CH3 NH Give the molecular formula of methylphenidate. List the functional groups present in methylphenidate.

How many stereogenic (chiral) centres are there in methylphenidate? Using a stereogenic centre you have identified, draw the (R)-configuration of that centre.

H

Ritalin is generally sold as the hydrochloride salt. Draw the structure of this salt and suggest why this is the preferred compound for sale.

Page Total:

Marks

7

CHEM1611

2012-J-8

2216(a)

 Show clearly the reagents you would use to carry out the following chemical conversions. Note that more than one step is required and you should indicate all necessary steps and the constitutional formulas of any intermediate compounds.

O Cl Cl

Page Total:

Marks

7

CHEM1611

2012-J-9

2216(a)

 The open chain form of D-talose is in equilibrium with two pyranose forms (L) and (M). Draw Haworth projections of (L) and (M). (L)

CHO HO

H

HO

H

HO

H

H

(M)

OH CH2OH

D-talose

Give the Haworth stereoformula of one of the products obtained when D-talose is treated with excess methanol in the presence of an acid catalyst.

Concentrated HNO3 oxidises aldehydes and primary alcohols to carboxylic acids, but does not oxidise secondary alcohols. Treatment of either D-talose or the aldohexose D-altrose with concentrated HNO3 gives the diacid (N). Give the Fischer projection of D-altrose. COOH

(N )

HO

H

HO

H

HO

H

H

OH COOH

Draw the Haworth stereoformula of a non-reducing disaccharide formed from D-talose.

Page Total:

Marks

7

CHEM1611

2012-J-10

2216(a)

 Cholecystokinin tetrapeptide (CCK-4), (Phe-Asp-Met-Trp) is a peptide fragment derived from the larger peptide hormone cholecystokinin. Unlike cholecystokinin, which has a variety of roles in the gastrointestinal and central nervous systems, CCK-4 acts primarily in the brain as an anxiogenic.

O

OH

O H2N

N H

H N

NH O N H

O

OH

CCK-4

O

S

Draw the Fischer projections of the four L-amino acids that result from the acid hydrolysis of CCK-4.

THIS QUESTION CONTINUES ON THE NEXT PAGE.

Page Total:

Marks

6

CHEM1611

2012-J-11

2216(a)

What is the major species present when aspartic acid (Asp) is dissolved in water at pH 12 and pH 1? The pKa values of aspartic acid are 1.88 (-COOH), 9.60 (-NH3) and 3.65 (side chain). pH 12

pH 1

Give the constitutional formulas for the following dipeptides in their zwitterionic states. Trp-Asp

Met-Phe

THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

Page Total:

Marks

4

CHEM1611

2012-J-12

2216(a) Marks

 Shown below is the structure of caffeine. O H 3C O

5 CH3 N

N

caffeine N

N

CH3 Draw the structure of a 10 electron aromatic resonance contributor to the structure of caffeine.

Only one of the nitrogen atoms in caffeine is basic. Indicate which of the nitrogen atoms is basic and explain why it is basic and why the others are not.

THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

Page Total:

2216(b)

June 2012

CHEM1611 - CHEMISTRY 1A (PHARMACY)

DATA SHEET Physical constants Avogadro constant, NA = 6.022  1023 mol–1 Faraday constant, F = 96485 C mol–1 Planck constant, h = 6.626  10–34 J s Speed of light in vacuum, c = 2.998  108 m s–1 Rydberg constant, ER = 2.18  10–18 J Boltzmann constant, kB = 1.381  10–23 J K–1 Permittivity of a vacuum, 0 = 8.854  10–12 C2 J–1 m–1 Gas constant, R = 8.314 J K–1 mol–1 = 0.08206 L atm K–1 mol–1 Charge of electron, e = 1.602  10–19 C Mass of electron, me = 9.1094  10–31 kg Mass of proton, mp = 1.6726  10–27 kg Mass of neutron, mn = 1.6749  10–27 kg

Properties of matter Volume of 1 mole of ideal gas at 1 atm and 25 C = 24.5 L Volume of 1 mole of ideal gas at 1 atm and 0 C = 22.4 L Density of water at 298 K = 0.997 g cm–3

Conversion factors 1 atm = 760 mmHg = 101.3 kPa

1 Ci = 3.70  1010 Bq

0 C = 273 K

1 Hz = 1 s–1

1 L = 10–3 m3

1 tonne = 103 kg

1 Å = 10–10 m 1 eV = 1.602  10

1 W = 1 J s–1 –19

J

Decimal fractions Fraction –3

Prefix

Decimal multiples

Symbol

10 10–6

milli micro

m

10–9

nano

n

pico

p

10

–12



Multiple 106

Prefix

Symbol

3

kilo M

k

109

giga

G

10 mega

2216(b)

June 2012

CHEM1611 - CHEMISTRY 1A (PHARMACY) Standard Reduction Potentials, E Reaction Co3+(aq) + e–  Co2+(aq)

E / V +1.82

Ce4+(aq) + e–  Ce3+(aq)

+1.72

MnO4–(aq) + 8H+(aq) + 5e–  Mn2+(aq) + 4H2O

+1.51

Au3+(aq) + 3e–  Au(s)

+1.50

Cl2 + 2e–  2Cl–(aq)

+1.36

O2 + 4H+(aq) + 4e–  2H2O

+1.23

Pt2+(aq) + 2e–  Pt(s) +

+1.18 –

MnO2(s) + 4H (aq) + e  Mn

3+

+ 2H2O

+0.96

NO3–(aq) + 4H+(aq) + 3e–  NO(g) + 2H2O Pd2+(aq) + 2e–  Pd(s)

+0.96 +0.92

Ag+(aq) + e–  Ag(s)

+0.80

3+

–

2+

Fe (aq) + e  Fe (aq)

+0.77

Cu+(aq) + e–  Cu(s)

+0.53

Cu2+(aq) + 2e–  Cu(s) +

+

+0.34 –

BiO (aq) + 2H (aq) + 3e  Bi(s) + H2O

+0.32

Sn4+(aq) + 2e–  Sn2+(aq)

+0.15

2H+(aq) + 2e–  H2(g)

0 (by definition)

3+

–

Fe (aq) + 3e  Fe(s)

–0.04

Pb2+(aq) + 2e–  Pb(s)

–0.13

Sn2+(aq) + 2e–  Sn(s)

–0.14

2+

–

–0.24

2+

–

Cd (aq) + 2e  Cd(s) Fe2+(aq) + 2e–  Fe(s)

–0.40 –0.44

Cr3+(aq) + 3e–  Cr(s)

–0.74

Ni (aq) + 2e  Ni(s)

2+

–

Zn (aq) + 2e  Zn(s) 2H2O + 2e–  H2(g) + 2OH–(aq) 2+

–

Cr (aq) + 2e  Cr(s)

–0.76 –0.83 –0.89

Al3+(aq) + 3e–  Al(s)

–1.68

Sc3+(aq) + 3e–  Sc(s)

–2.09

Mg2+(aq) + 2e–  Mg(s)

–2.36

+

–

Na (aq) + e  Na(s)

–2.71

Ca2+(aq) + 2e–  Ca(s)

–2.87

Li+(aq) + e–  Li(s)

–3.04

2216(b)

June 2012

CHEM1611 - CHEMISTRY 1A (PHARMACY) Useful formulas Quantum Chemistry

Electrochemistry

E = h = hc/

G = –nFE

 = h/mv

Moles of e– = It/F

E = –Z2ER(1/n2)

E = E – (RT/nF)  lnQ

x(mv)  h/4

E = (RT/nF)  lnK

q = 4r2  5.67  10–8  T4

E = E –

6

T  = 2.898  10 K nm

0.0592 logQ (at 25 C) n

Acids and Bases

Gas Laws

pH = –log[H+]

PV = nRT

pKw = pH + pOH = 14.00

(P + n2a/V2)(V – nb) = nRT

pKw = pKa + pKb = 14.00

Ek = ½mv2

pH = pKa + log{[A–] / [HA]} Kinetics

Radioactivity

t½ = ln2/ 

t½ = ln2/k

A = N

k = Ae–Ea/RT

ln(N0/Nt) = t

ln[A] = ln[A]o – kt

14

C age = 8033 ln(A0/At) years

ln

k2 Ea 1 = ( - 1) k1 R T1 T2

Colligative Properties & Solutions

Thermodynamics & Equilibrium

 = cRT

G = H – TS

Psolution = Xsolvent  Psolvent

G = G + RT lnQ

c = kp

G = –RT lnK

Tf = Kfm

univS = R lnK

Tb = Kbm

RT n Kp = Kc ( ) 100

Miscellaneous

Mathematics

I A = –log I0

If ax2 + bx + c = 0, then x =

A = cl

ln x = 2.303 log x 2

E = –A

e

4  0 r

NA

Area of circle = r2 Surface area of sphere = 4r2

b 

b 2  4ac 2a

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

1

2

HYDROGEN

HELIUM

H

He

1.008

4.003

3

4

5

6

7

8

9

10

BERYLLIUM

BORON

CARBON

NITROGEN

OXYGEN

FLUORINE

NEON

Li

Be

B

C

N

O

F

Ne

6.941

9.012

10.81

12.01

14.01

16.00

19.00

20.18

LITHIUM

11

12

13

14

15

16

17

18

SODIUM

MAGNESIUM

ALUMINIUM

SILICON

PHOSPHORUS

SULFUR

CHLORINE

ARGON

Na

Mg

Al

Si

P

S

Cl

Ar

22.99

24.31

26.98

28.09

30.97

32.07

35.45

39.95

20

21

22

23

24

CALCIUM

SCANDIUM

TITANIUM

VANADIUM

CHROMIUM

K

Ca

Sc

Ti

V

Cr

Mn

39.10

40.08

44.96

47.88

50.94

52.00

54.94

37

38

39

40

41

42

43

NIOBIUM

MOLYBDENUM

RUBIDIUM

25 MANGANESE

26

27

30

31

32

33

IRON

COBALT

NICKEL

COPPER

ZINC

GALLIUM

GERMANIUM

ARSENIC

Fe

Co

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

55.85

58.93

58.69

63.55

65.39

69.72

72.59

74.92

78.96

79.90

83.80

44

45

46

47

48

49

50

51

52

53

54

SILVER

CADMIUM

28

29

34 SELENIUM

35

36

BROMINE

KRYPTON

STRONTIUM

YTTRIUM

ZIRCONIUM

TECHNETIUM

RUTHENIUM

RHODIUM

PALLADIUM

INDIUM

TIN

ANTIMONY

TELLURIUM

IODINE

XENON

Rb

Sr

Y

Zr

Nb

Mo

Tc

Ru

Rh

Pd

Ag

Cd

In

Sn

Sb

Te

I

Xe

85.47

87.62

88.91

91.22

92.91

95.94

[98.91]

101.07

102.91

106.4

107.87

112.40

114.82

118.69

121.75

127.60

126.90

131.30

55

56

57-71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

CAESIUM

BARIUM

HAFNIUM

TANTALUM

TUNGSTEN

IRIDIUM

PLATINUM

GOLD

MERCURY

THALLIUM

LEAD

BISMUTH

POLONIUM

ASTATINE

RADON

RHENIUM

OSMIUM

Cs

Ba

Hf

Ta

W

Re

Os

Ir

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Rn

132.91

137.34

178.49

180.95

183.85

186.2

190.2

192.22

195.09

196.97

200.59

204.37

207.2

208.98

[210.0]

[210.0]

[222.0]

89-103 104

87

88

FRANCIUM

RADIUM

RUTHERFORDIUM

105

106

107

108

109

110

111

112

DUBNIUM