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 2013/2014 : SEMESTER 1 ACADEMIC SESSION 2013/2014 : SEMESTER 1 SCES2245/ SCES2311 : PENGENALAN KEPADA KIMIA ANALISIS/ KIMIA ANALISIS AM INTRODUCTION TO ANALYTICAL CHEMISTRY/ GENERAL ANALYTICAL CHEMISTRY Disember 2013/Januari 2014 December 2013/January 2014 MASA : 2 jam TIME : 2 hours ARAHAN KEPADA CALON : INSTRUCTIONS TO CANDIDATES: Kertas soalan ini mengandungi Bahagian A and Bahagian B. This question paper consists of Section A and Section 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 7 soalan dalam 5 halaman yang dicetak) (This question paper consists of 7 questions on 5 printed pages)
BAHAGIAN A (50 MARKAH) SECTION A (50 MARKS) Jawab SEMUA soalan daripada bahagian ini. Answer ALL questions from this section. 1. (a) Terangkan perbezaan di antara kaedah potentiometrik dan voltametrik. Discuss the differences between potentiometric and voltammetric method. (9 markah/marks) Mengapa elektrod ph kaca perlu direndam di dalam air sebelum digunakan? Why is it necessary to immerse a ph glass electrode in water before use? 2. (a) Bincangkan dua sumber arus residu dalam polarografi. Discuss two sources of residual current in polarography. (5 markah/ marks) Terangkan fungsi counter electrode dan elektrolit pembantu dalam kaedah voltametrik. Explain the function of counter electrode and supporting electrolyte in voltammetric method. (c) Bincangkan maklumat yang boleh didapati daripada voltamogram. Discuss the information that we can get from a voltammogram. (4 markah/marks) 3. (a) Terangkan dua sistem asas dalam sistem pengekstrakan pelarut bagi ion logam. Berikan contoh bagi setiap satu. Describe two principal solvent extraction systems for metal ions. Give examples of each. (10 markah/marks) 2/5
Terangkan prinsip asas bagi kromatografi penukaran ion. Describe the basic principles of ion exchange chromatography. (d) Senaraikan lima sifat pengesan yang ideal yang harus ada bagi kromatografi gas. List five characteristics that an ideal detector should have in gas chromatography. BAHAGIAN B (50 MARKAH) SECTION B (50 MARKS) Jawab SEMUA soalan. Answer ALL questions. 4. (a) Terangkan secara ringkas perbezaan antara setiap daripada dua istilah di bawah: Explain briefly the differences between each of the following pair of terms below: (i) (ii) (iii) (iv) Sampel dan analit Sample and analyte Kejituan dan ketepatan Precision and accuracy Ralat tentu dan ralat tak tentu Determinate error and indeterminate error Takat akhir dan takat setara End point and equivalence point (12 markah/marks) Jelaskan bagaimana untuk mendapatkan sampel yang dipilih adalah mewakili sampel bahan sebenar dalam suatu kimia analisis. Explain how to get a selected sample to be representative of the real material in a chemical analysis. (3 markah/marks) 3/5
5. (a) Suatu analisis bagi merkuri dalam sampel air memberikan nilai 1.20 ppb(w/v). Hitung jisim merkuri terdapat dalam 1.00 L air. An analysis for mercury in a water sample gave a value of 1.20 ppb(w/v). Calculate the mass of mercury present ini 1.00 L of water? Pentitratan 50.00-mL alikuot suatu akueus asid sulfurik, H 2 SO 4, memerlukan 42.20 ml KOH berkepekatan 0.1645 N. Hitung kemolaran larutan asid sufurik tersebut. A titration of 50.00-mL aliquot of an aqueous sulfuric acid, H 2 SO 4, requires 42.20 ml of 0.1645 N KOH. Calculate the molarity of the sulfuric acid solution. 6. (a) Jelaskan hubungkait antara kepekatan dan transmitan merujuk kepada hukum Beer-Lambert s. Explain the relationship between concentration and transmittance by refering to Beer-Lamber s law. Lakar dan labelkan gambarajah blok spektrometer penyerapan atom nyalaan. Terangkan secara ringkas prinsip dalam spekrometri penyerapan atom nyalaan. Sketch and label a block diagram of a flame atomic absorption spectrometer. Describe briefly the principle of flame atomic absorption spectrometry. (10 markah/marks) 7. (a) Hitung sisihan piawai relatif (%) bagi satu set data replikat berikut. Calculate the relative standard deviation (%) of the following replicate set of data. Kandungan kadmium/ppm: Cadmium content/ppm: 4.346 4.362 4.379 4.335 4.341 Komen kejituan pengukuran tersebut. Comment upon the precision of the measurement. 4/5
Hitung julat keyakinan (90%) terhadap purata data dalam soalan 7(a). Calculate the confidence interval (90%) about the mean of the data in question 7(a). (4 markah/marks) TAMAT END 5/5