UNIVERSITI MALAYA UNIVERSITY OF MALAYA PEPERIKSAAN IJAZAH SARJANA MUDA SAINS EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE SESI AKADEMIK 2015/2016 ACADEMIC SESSION 2015/2016 : SEMESTER II : SEMESTER II SCES3141/SCES3311 : KIMIA ANALISIS LANJUTAN/ KIMIA ANALISIS II ADVANCED ANALYTICAL CHEMISTRY/ ANALYTICAL CHEMISTRY II Jun 2016 June 2016 Masa: 2 jam Time: 2 hours ARAHAN KEPADA CALON: INSTRUCTIONS TO CANDIDATES: Jawab SEMUA soalan. Answer ALL questions. (Kertas ini mengandungi 5 soalan dalam 5 halaman yang dicetak) (This question paper consists of 5 questions on 5 printed pages)
1. a) Terangkan prinsip bagi spektroskopi penyerapan atom nyala (FAAS). Describe the principle of flame atomic absorption spectroscopy (FAAS). (10 markah/marks) b) Lampu katod berongga memainkan peranan penting dalam spektroskopi penyerapan atom. Bincangkan. c) The hollow cathode lamp plays an important role in atomic absorption spectroscopy. Discuss. Gambar rajah di atas menunjukkan graf penentukuran bagi Cd. Bincangkan peranan KCl dalam analisis ini. The figure above shows the calibration curve of Cd. Discuss the role of KCl in this analysis. (6 markah/marks) 2. (a) Spektroskopi pemancaran atom telah digunakan secara meluas untuk analisis kualitatif berbanding spektroskopi penyerapan atom. Huraikan pernyataan di atas. Atomic emission spectrocopy has been widely used for qualitative analysis compared to atomic absorption spectroscopy. Elaborate the abovementioned statement. 2/5
Apakah fungsi nyala dalam spektroskopi pemancaran atom nyala? Mengapakah pemancaran atom lebih peka terhadap ketidakstabilan nyala daripada penyerapan atom. What is the function of flame in flame atomic emission spectoscopy? Why is atomic emission more sensitive to flame instability than atomic absorption. Apakah tujuan piawai dalaman di dalam analisis yang melibatkan spektroskopi pemancaran atom? What is the purpose of an internal standard in analysis involving atomic emission spectoscopy? (d) Terangkan mengapa gangguan kimia jarang berlaku dalam ICP-AES berbanding FAAS. Explain why chemical interferences are less common in ICP-AES than they are in FAAS. 3. (a) Apakah Fasa Kromatographi Terbalik? Jelaskan. What is the Reversed Phase Chromatography? Explain. (5 markah/marks) Apakah prinsip pemisahan dalam Saiz Pengecualian Chromatography? What is the separation principle in Size Exclusion Chromatography? (5 markah/marks) Berikan empat ciri-ciri wajar bagi fasa bergerak HPLC? Terangkan perbezaan antara elusi isokratik dan gradien. Give four desirable characteristics of HPLC mobile phase? Explain the different between isocratic and gradient elution. (10 markah/marks) 3/5
4. (a) Apakah empat (4) perbezaan utama di antara Kromatographi Cecair Berpretasi Tinggi (HPLC) dan Kromatographi Gas (GC)? What are the four (4) main differences between High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC)? Terangkan bagaimana pengaturcaraan suhu dapat memperbaiki pemisahan dalam kromatografi gas. How does temperature programming improves separation in gas chromatography? Terangkan prinsip bagi pengesan kromatografi gas berikut: Describe the principle of the following gas chromatography detectors: (i) (ii) konduktiviti terma thermal conductivity pengionan nyala flame ionization 5. (a) Bezakan antara voltammetri dan polarografi. Distinguish between voltammetry and polarography. (3 markah/marks) Senaraikan kelebihan dan kekurangan elektrod titisan raksa (DME) berbanding dengan elektrod lengai seperti dawai Pt atau kepingan karbon. List out the advantages and limitations of dropping mercury electrode (DME) over an inert electrode such as Pt wire or carbon plate. (6 markah/marks) Mengapa kaedah pelucutan lebih sensitif daripada analisis voltammetri yang lain? Why are stripping methods more sensitive than other voltammetric analysis? 4/5
(d) Fe(III) di dalam sampel sebanyak 0.9811 g telah ditukarkan ke Fe(II) oleh penurunan coulometri pada katod platinum. Kirakan peratusan Fe 2 (SO 4 ) 3 (MW = 399.88 g/mol) dalam sampel jika 115.9355 C diperlukan untuk penurunan tersebut. (Diberikan pemalar Faraday = 96485 C/mol) The Fe(III) in a 0.9811 g sample was determined by coulometric reduction to Fe(II) on a platinum cathode. Calculate the percentage of Fe 2 (SO 4 ) 3 (MW = 399.88 g/mol) in the sample if 115.9355 C were required for the reduction. (Given Faraday constant = 96485 C/mol) TAMAT END (7 markah/marks) 5/5