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UNIVERSITI MALAYSIA PERLIS

Peperiksaan Semester Pertama Sidang Akademik 201112012

17 Januari 2012

EDT 238-Physical Chemistry [Kimia Fizikal]

Masa : 3jam

Please make sure that these question paper have THIRTEEN (13) printed pages including this front page before you start the examination. [Silo pas/ikon kertas soalan ini mengandungi TlGA. BELAS (/3) muka sural yang tercetak termasuk mulca hadopan sebelum anda memulalcan peperiksaan ini.}

This question paper has SIX (6) questions. Answer any FIVE (5) questions only. Each question contributes 100 marks. [Kertas soalan in; mengandungi ENAM (6) soalan. Jawab IIIIIIItHlUllfll UMA (5) soalan sahqja. Marlcah bagi tiop-tiop soalan addah 100 marlcah}.

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Question 1 (SofIltm J)

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(a) Differentiate the following concentration terms: [Bezakan istilah-istilah kepekatan berilcut:]

i. Mole fraction [pecahan mol]

ii. Molarity [Kemolaran]

iii. Molality [~moIalan]

iv. Normality [Kenormalan]

[EBT238)

(20 Marks] [20 Markah]

(b) The label on a bottle of aqueous hydrochloric acid, HeI, gives concentration as 37 percent by weight, and density of the solution is 1.19 glml. Calculate the following:

[Label pada botol asid hidroldorik, Hel. diberi kepekatan adalah 37 peratus berat, dan ketumpatan larutan adalah 1.19 glml. l(jrakan yang berilcut:]

i. Molarity [Kemolaran]

ii. Molality [Kemolalan]

iii. Mole fraction [Pecahan mol]

[30 Marks] {JOMarkah]

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(c) The mass percentage composition of dry air at sea level is approximately N2 75.5; 02 23.2; Ar 1.3. Calculate the partial pressure of each component when the total pressure is 1.000 atm (Relative atomic mass: N=14, 0=16, Ar=39.95). [Komposisi peratus jiaim udara /rering pada paras lout adaJah dianggarkan N2 75.5: 0 2 23.2; Ar 1.3. Kirakan tekanan separa aetiap komponen apabi/ajum/ah teMnan adalah 1.000 aJm (Jisim atom relative: N=14. 0=16, Ar=39.95)].

(30 Marlm] {30Markah]

(d) Henry's law constant for nitrogen at 20 °C is 5.75 X 107• Calculate how many

grams nitrogen would dissolve in 100 g of water at 20 OC, if the partial pressure of nitrogen in the solution is 750 mm Hg? [Pemolar hulrMm Henry untuk nitrogen pada 20 OC adalah 5.75 x 107

• Kirakan berapa gram nitrogen akan iarut dalam air pada 20 oc, jiM tekanan separa nitrogen dalam /arutan adalah 750mmHg?]

(20 MaraJ [20Markah]

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Question 2 (SOfIItIn 2)

(a) Contrast the following terms: [Bandingiwn istilah-istilah berikut:]

(EBT 238] -4-

1. Number average molecular weight and weight average molecular weight of polymer. [Purata nombor berm molelrul dan purata berat berat molelrul polimer]

it Intrinsic viscosity and Inherent viscosity [Kelikatan intrinsik dan Kelikatan semuiajadij

[20 Marks] [20 Markahj

(b) The concentration data for solutions of polystyrene (PS) in toluene was measured at 30°C and the results obtained are summarized in Table 1. Analyze and determine the intrinsic viscosity of this PS sample and the value of the Huggins constant, kH. [Data 1repekatan bag; lanttan polistirena (PS) da/am toluena telah disukat pada 30 OC dan lceputusan yang diperolehi te/ak diringkaskan dalam JadruJI 1. Analisa dan tentukan 1relikatan intrinsik sampel PS ini dan nilai pemalar Huggins, kB.]

Table 1: Concentration data obtained for solutions of polystyrene in toluene [JaduaJ 1: Pengukuran lrepekatan yang diperolehi untuk lanttan polistirena daJam toluena]

Concentration (g elL-I) [Kepe1catan (g dL-1

))

0 0.54 1.08 1.62 2.16

Time (s) [Masa(s)]

65.8 101.2 144.3 194.6 257.0

[50 Marks] [SO Markah]

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(c) A polydisperse sample of polystyrene is prepared by mixing five monodisperse samples in the following proportions: [Sampel polisebaran poIisdrena disedia/a:m melalui campuran lima sampe/ monosebaran dolam nisbah berilt:ut:]

Sample Molecular weight Mass (g) (gImole)

1 10,000 1.0 2 50,000 2.0 3 100,000 3.0 4 250,000 4.0 5 300,000 5.0

Estimate the number-average molecular weight and weight-average molecular weight. Calculate polydispersity index (PDI) of the mixture. [Anggarkon purata nombor berat molekul don purata bera! berat molelr:ul. Kirakon indelrs kepolisebaran canrpuran tersebut]

[30 Marks) [JOMarkah]

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Question 3 (Soala"J)

(a) Compare the following tenns: [Bandingkan yang istilah-istilah berikut:]

i. Phase and component [Fasa dan komponen]

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ii. Liquid-liquid extraction and solid-liquid extraction [Penyarian cecair-cecair dan penyarian pepeja/-cecair]

(b) Analyze possible components present in the following systems:

(EBT238]

(20 MarksJ [20 Marlcah]

[Ana/isa komponen-komponen yang berlcemungldnan hadir dalam sistem-sistem berikut:]

i. Water, allowing for its ionization [Air, dibenarkan pengionannya]

ii. Sucrose in water [Sukrosa dalam air]

iii. Sodium chloride in water [Sodium kJorida daJam air]

iv. Aqueous phosphoric acid [Asidfosforik aJcuas]

(20 MarksJ [20 Marlcah]

(c) Construct the extraction process for liquid and solid samples using appropriate method. [Binakon proses penyarian unluk sampel cecair dan sampel pepeja/ menggunakan koedah yang bersesuaian]

[20 MarksJ [20 Marlcah]

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(d) The distribution ratio for iodine (12) between water and carbon disulfide (CS2) is 650. Estimate the concentration of 12 remaining in the aqueous phase after 50.0 mL of 0.10 M h in water is shaken with 10.0 mL ofCS2. [Nisbah pengagihan untuk iodin amara air dan karbon disulfida adalah 650. Anggarkan lrepekatan 12 yang masih berbaki dalam fasa alroas selepas 50.0 mL 0.10 M 12 air digoncangkan dengan 10.0 mL CS,.]

[20 Marks) [20 Markah]

( e) Calculate the de Broglie wavelength of an electron that bas been accelerated through a potential difference of 100 V (Mass of electron= 9.109 XIO-31 kg). [Kirakan jarak gelombang de Broglie elelctron yang dipecutkan melalui perbezaan lreupayaan 100 V (Jisim elelctron= 9.109 X1U31 kg).]

(20 Marks] [20 Marlrah]

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Question 4 (SoaItm4)

(EBT238) -8-

<a) Relate the following reaction are redox reaction, for each of the redox reaction identified label the reducing agent and oxidizing agent; [Huhungkan mengileuti tindak halas adalah pengoksidaan dan penunman, untuk aetiap tindak halas redoks dan !renal pasti agen penurunan atau agen pengoksidaan?]

ii. H2Se03 (s) +H2S <aq) ~ S (s) + Se (s)

iii. KI (s)+ HF (aq)~ KF (s) + HI (aq)

(30 Marks) [JOMarkah]

<b) Balance the following equation in acidic environment. Predict the oxidizing agent and reduction agent. [Imhangkan persamaan herileut dalam peraeldtaran herasid Jangkakan agen pengoksidaan dan agen penurunan]

KMn04 (s) + HBr (aq)+ Sn2+ (aq) ~ Mn2+ (aq) + Sn 4+ (aq)

(10 Marks] [20 Markah]

(c) Calculate the equilibrium constant for the galvanic cell AI (8) /AI3+ /I Sn2+/Sn(s) at standard conditions. (Sn2+/Sn = - 0.14 volt and AI3+/AI = - 1.66 volt) (l'entukan pemalar lreseimhangan untuk Sel Galvanik AI (a) IAr II S,(+ISn (a) pada !readaan piawai). (S,(+ISn = -O.14voltandAf+IAI ='- 1.661101t))

[20 Marks] [20 Markah]

(d) Calculate the standard emf of an electrochemical cell made of a Cd electrode in a 1.0 M Cd(N03)2 solution and a Cr electrode in a 1.0 M Cr(N03)3 solution? (E°Cd2+(aq) / Cd (s) = -0.40 v and EOC"+(aq) / Cr (s) = -0.74 v) [Kirakan piawai emf dan ael elekJroldmia yang dihuat dari elekJrod Cd dalam Ianltan Cd(NOsh 1.0 M dan eleklrod Cr dalam larutan Cr(NOsh 1.0 M. (E'Ctr (aq) I Cd (8) = -0.40 v dan E'C,J+ (aq) / Cr (a) = -0.74 11)]

[10 Marks) [10 Markah]

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(e) The following data were obtained on the rate of hydrolysis of 17% sucrose in 0.099 mol/L HCI aqueous solution at 35 °C.(See Table 2) [Data berikut diperoleh doripada kodar penguraian 17% sukrosa dol am larutan akuas 0.099 moVL HCI pada suhu 3SOC).[Lihat Jadual1]

Table 2: Data of hydrolysis of 17% sucrose solution [Jadual1: Data hidrolisis 17% larutan sukrosa]

Time (min) Sucrose(%) [Masa (min)] [Sukrosa (OAI)]

9.8 96.5 59.6 80.3 93.1 71.0 142.9 59.1 294.8 32.8 590.0 11.1

Calculate the value of the rate constant (k) [Kira nilai pemalar /radar (k)]

[20 Marksl [10 Markah]

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Question 5 ISOtllall 5/

(EBT238) -10 -

(a) In studying the decomposition of ozone 203 (g).. • 3(h (g) in a 2 L reaction vessel, it is found that d[Od/dt = -1.5 x 10-2 mol L"I S-I. [Da/am mempelajari penguraian ozon 20'l~" .. 302fg) dalam 2 L cawan tindak balas. didapati bahawa d[OJ/dt = -1.5 x Iff2 mol C S-I J

i. Calculate the rate of reaction [Kirakan kadar tindak balas]

ii. Calculate the rate of conversion {Kirakan kadar penukaran]

iii. Determine the value of d[021/dt [Tentukan nila; d[oiJ/dt}

(20 Marks) [20 Marleah)

(b) Suppose the transformation of A to B occurs by both a reversible first-order reaction and a reversible second-order reaction involving hydrogen ion. [Andaikan transformasi A Ice B terjadi oleh lcedua tinda/c balos perintah pertama dan perintah lcedua boleh balik yang meliputi ion hldrogen}

A •• =::::p!' B A+W ... =:::e:. B+W

Evaluate the relationship between these four rate constants. {Nilallean hubungan antara empat pemalar lcadar dalam tindak balas tersebut}

(20 Marks] [20 Marlcah]

(c) If a first-order reaction has activation energy of 104,600 J morl and a pre­exponent factor A of 5 x 1013 S-I. Calculate the temperatures will the reaction have a half-life of <a) lmin and (b) 30 days. (Jilea tindak balos perintah pertama memilild tenaga pengalctifan 104.600 J morl dan faktor eksponen bebas A adalah 5 x loI' S-I. Kirakan suhu tindak balas pada separuh hayat (a) I min dan (b) 30 hari]

[30 Marks] {30Markah]

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(d) Determine the rate law and calculate the rate constant for the following reaction by using the data in Table 3. {I'entukan hukum kaJar dan kirakan pemalar Icadar untuk timiak balos berikut dengan menggunakan data dalam Jadual 3J

Exp. [EksperimenJ

1 2 3

Table 3: Data of experiment [Jadual 3: Data eksperimenJ

(S:z08~ P1 Initial rate (M/s] [Kadar awalJ (MIs1

0.08 0.034 2.2 x 10"" 0.08 0.017 1.1 x 10 .... 0.16 0.017 2.2 x 10 ....

(30 Marks] [30 MarlcahJ

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Question 6 [Soalan6]

[EBT238] - 12-

(a) Predict the effect of linear and branched molecule on the adsorption and micellization. [Jangl«llcan pengaruh molekuJ linear and bercabang terhadop pe,,;erapan and misellisasij

[20 Marks] [20 Markah]

(b) Compare the ionic surfactant and non-ionic surfactant in the adsorption system. [Bandinglcan surfaktan berionik and surfaktan tidak berionik da/am sistem penjerapan]

[20 Marks) [20 Marl«lh]

(c) Calculate the solubility parameter for a methyl methacrylate-butadiene copolymer containing 25 mol% methyl methacrylate. The solubility for poly(methhl methacrylate) and polybutadiene homopolymer are 9.3 and 8.4 (cal.cm-3)1

,

respectively. ( Mw MMA =100 glmol and Mw Butadiene = 54 glmol) [Kiralcan parameter lrebolehlarutan untuk /copolimer metil metakrilat-butadiena yang mengandungi metil metobilat 25% moL Kebolehlarutan untulc seti~ homopolimer poli(metil metakrilat) don polibutadiena setiapnya adolah 9.3 and 8.4 (cal.cni3Y ). [Mw MMA =100 Wmol and Mw Butadiena = 54 Wmol]

(d) Compare the amphipathic and amphiphilic of the surfactant. [Bandingl«ln atrifipat;k don amfifilik surfaklan]

(20 Marks] [20 Markah]

[20 Marks) [20 Marlcah]

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(e) Calculate the osmotic pressure ofa solution of 10.0 g glucose (C6H1206) in 1000 cm3 of water at 1 atm and 2SoC. (Mw glucose = 180 glmol). [Kirakan tekanan osmotik larutan 10.0 g glukosa dalam 1000 c"! air pada 1 aim dan 2S'C. (Mw glukosa = 180 Wmol).}

[20 Marks) [20 Marlcah}

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