UNIVERSITI MALAYA UNIVERSITY OF MALAYA PEPERIKSAAN IJAZAH SARJANA MUDA SAINS EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE PEPERIKSAAN IJAZAH SARJANA MUDA SAINS DENGAN PENDIDIKAN EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE WITH EDUCATION SESI AKADEMIK 2015/2016 : SEMESTER 1 ACADEMIC SESSION 2015/2016 : SEMESTER 1 SCES2211/ SCES2241/SCES2245 : KIMIA ANALISIS I / KIMIA ANALISIS ASAS / PENGENALAN KEPADA KIMIA ANALISIS ANALYTICAL CHEMISTRY I / BASIC ANALYTICAL CHEMISTRY / INTRODUCTION TO ANALYTICAL CHEMISTRY Dis 2015/ Jan 2016 Dec 2015/ Jan 2016 MASA : 2 jam TIME : 2 hours ARAHAN KEPADA CALON : INSTRUCTIONS TO CANDIDATES : Kertas soalan ini mengandungi Bahagian A dan B. This paper consists of Section A and B. Jawab soalan mengikut arahan yang diberikan dalam setiap bahagian. Answer the questions according to the instructions given in each section. (Kertas soalan ini mengandungi 6 soalan dalam 6 halaman yang dicetak) (This question paper consists of 6 questions on 6 printed pages)
BAHAGIAN A (50 MARKAH) SECTION A (50 MARKS) Jawab semua Tiga (3) soalan daripada bahagian ini Answer all Three (3) questions from this section SCES2211/SCES2241/SCES2245 1. (a) Jelaskan mengapa perpisahan diperlukan dalam kimia analisis dan berikan beberapa contoh teknik pemisahan. Explain why separation is used in analytical chemistry and provide some examples of separation techniques. (5 markah/marks) Satu larutan akueus mempunyai kepekatan sama A dan B. D A = 100; D B = 0.1; V aq = V org. Apakah yang berlaku dalam dua pengekstrakan berturut-turut? Jika ekstrak organik 'dibasuh-balik' dengan fasa akueus segar, apakah kesan countercurrent fractionation kepada kecekapan dan pemilihan? Tunjukkan pengiraan bagi kedua-dua pengekstrakan berturut-turut dan pemeringkatan berlawanan untuk menyokong hujah anda. An aqueous solution has equal concentrations of A and B. D A = 100; D B = 0.1; V aq = V org. What happens in two successive extractions? If the organic extract is back-washed with fresh aqueous phase, what is the effect of countercurrent fractionation on efficiency and selectivity? Show the calculations for both the successive extractions and countercurrent fractionation to support your argument. Diberi: Given: Keberkesanan pengekstrakan Efficiency of extraction p = D D+( V aq Vorg ) p adalah pecahan daripada analit (apa-apa bentuk) dipindahkan ke fasa organik selepas keseimbangan. q adalah pecahan daripada analit (apa-apa bentuk) tinggal dalam fasa akueus selepas keseimbangan. p is the fraction of analyte (any form) transferred to the organic phase after equilibration. q is the fraction of analyte (any form) left in the aqueous phase after equilibration. 2/6
SCES2211/SCES2241/SCES2245 2. (a) Bincangkan apakah kepentingan teknik GC dan HPLC. Discuss the importance of GC and HPLC techniques. Dalam teori kadar kromatografi, bincangkan secara terperinci apakah faktor-faktor penting yang menyumbang kepada pelebaran band? In rate theory of chromatography, discuss in detail what are the important factors which contribute to band broadening? 3. (a) Apakah ciri-ciri gelombang voltametri siklik (CV) berbalik? Dalam sistem berbalik, apakah kesan dari kadar imbasan ( ) dan kinetik, terhadap CV? What are the characteristics of a reversible cyclic voltametry (CV) wave? In a reversible system, what is the effect of scan rate ( ) and kinetics, respectively to CV? (8 markah/marks) Apakah yang dimaksudkan pelucutan analisis dan mengapa prakepekatan diperlukan? Berikan tiga contoh pelucutan voltammetri. What is stripping analysis and why pre-concentrate is needed? Provide three examples of stripping voltammetry. (7 markah/marks) 3/6
BAHAGIAN B (50 MARKAH) SECTION B (50 MARKS) Jawab semua Tiga (3) soalan daripada bahagian ini Answer all Three (3) questions from this section SCES2211/SCES2241/SCES2245 4. (a) Jelaskan konsep unit yang biasa digunakan oleh ahli kimia seperti berikut. Define the following concepts of common units used by a chemist. (i) (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) (x) Kemolaran (M) Molarity (M) Formaliti (F) Formality (F) Normaliti (N) Normality (N) Molaliti (m) Molality (m) Bahagian per juta (ppm) Parts per million (ppm) Bahagian per billion (ppb) Parts per billion (ppb) Bahagian per trilion (ppt) Parts per trillion (ppt) Peratus berat (w/w) Weight percent (w/w) Peratus isipadu (v/v) Volume percent (v/v) Berat/Isipadu peratus (w/v) Weight/Volume percent (w/v) 4/6
SCES2211/SCES2241/SCES2245 Kirakan kepekatan molar HNO 3 (MW = 63.5 g mol -1 ) dalam larutan yang mempunyai graviti spesifik 1.42 dan 70.5% HNO3 (w/w). Calculate the molar concentration of HNO 3 (MW = 63.5 g mol -1 ) in a solution that has a specific gravity of 1.42 and is 70.5 % HNO 3 (w/w). (5 markah/marks) 5. (a) Keputusan berikut diperolehi dalam penentuan ulangan kandungan utama daripada sampel darah: 0,752, 0,756, 0,752, 0,751 dan 0,760 ppm Pb. Kira: The following results were obtained in the replicate determination of the lead content of a blood sample: 0.752, 0.756, 0.752, 0.751, and 0.760 ppm Pb. Calculate: (i) (ii) (iii) (iv) (v) (vi) Purata the mean sisihan piawai the standard deviation varians the variance sisihan relatif standard di bahagian-bahagian setiap seribu the relative standard deviation in parts per thousand koefisien variasi the coefficient of variation, and median the median (20 markah/marks) 6. (a) Sampel dalam sel 1.0-cm ditentukan dengan spektrometer untuk menghantar 80% cahaya pada panjang gelombang tertentu. Jika keberserapan (a) bahan ini pada panjang gelombang ini adalah 2.0 cm -1 g -1 L, apakah kepekatan bahan dalam unit g L -1? A sample in a 1.0-cm cell is determined with a spectrometer to transmit 80% light at a certain wavelength. If the absorptivity (a) of this substance at this wavelength is 2.0 cm -1 g -1 L, what is the concentration of the substance in unit g L -1? (5 markah/marks) 5/6
SCES2211/SCES2241/SCES2245 Apakah perbezaan di antara Spektroskopi Serapan Atom (AAS) dan Atomic Pemancaran Spektroskopi (AES) dari segi definisi, sumber cahaya, pengabusan dan prinsip operasi? What is the difference between Atomic Absorption Spectroscopy (AAS) and Atomic Emission Spectroscopy (AES) in terms of definition, light source, atomization, and principle of operation? TAMAT END 6/6