SCES1200 : PRINSIP-PRINSIP KIMIA PRINCIPLES OF CHEMISTRY

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1 UNIVERSITI MALAYA UNIVERSITY OF MALAYA PEPERIKSAAN IJAZAH SARJANA MUDA SAINS EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE SESI AKADEMIK 2010/2011 : SEMESTER 1 ACADEMIC SESSION 2010/2011 : SEMESTER 1 SCES1200 : PRINSIP-PRINSIP KIMIA PRINCIPLES OF CHEMISTRY November/ Disember 2010 November/ December 2010 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. Questions should be answered 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)

2 SCES1200/ 02 BAHAGIAN A (50 MARKAH) SECTION A (50 MARKS) Jawab SEMUA soalan. Answer ALL questions. 1. (a). Huraikan perubahan dalam sifat logam ke bukan logam apabila merentasi Jadual Berkala bagi unsur-unsur kumpulan utama. Describe the change in metallic and non-metallic character in going across the Periodic Table for the main group elements (b). Namakan unsur-unsur berikut seperti yang diwakilkan oleh simbol-simbol berikut: Name the following elements as represented by the symbols: Ru Ga (iii) Te (iv) Pr (v) Sm (vi) Nd (vii) In (c). (d). (e). Hitungkan Cas Nuklear Berkesan bagi oksigen. Calculate the Effective Nuclear Charge for oxygen. Huraikan tren dalam jejari atom apabila merentasi Jadual Berkala. Describe the trend in atomic radii in going across the Periodic Table. Bagi unsur-unsur Kumpulan 4A, huraikan variasi dalam struktur oksidaoksida ini. Lukiskan struktur bagi menggambarkan jawapan anda. For the Group 4A elements, describe the variation in the structures of the oxides of the elements. Draw their structures to illustrate your answers. (35 markah/ marks) 2. Satu larutan akueus mengandungi 5.50 g kalsium klorida, CaCl 2, per liter. Apakah kemolaran CaCl 2? Apabila kalsium klorida melarut dalam air, apakah kemolaran setiap ion? An aqueous solution contains 5.50g of calcium chloride, CaCl 2, per litre. What is the molarity of CaCl 2? When calcium chloride dissolves in water, what is the molarity of each ion? [Ca = 40, Cl = 35.5]

3 SCES1200/ Anda ingin menyediakan 0.15M HNO 3 dari larutan stok 15.5M asid nitrik. Apakah isipadu larutan stok yang diperlukan bagi membuat 1.00L larutan 0.15M HNO 3? You want to prepare 0.15M HNO 3 from a stock solution of 15.5M nitric acid. What is the volume of the stock solution required to make 1.00 L of 0.15 M HNO 3? 4. Suatu sampel 3.20 g bijih besi dilarutkan bagi membentuk larutan FeSO 4 dan larutan ini dititrat dengan 0.120M K 2 Cr 2 O ml K 2 Cr 2 O 7 diperlukan bagi mentitrat FeSO 4. Tentukan peratus ferum dalam bijih ini. A 3.20 g sample of iron ore is dissolved to form a solution of FeSO 4 and this solution is then titrated with 0.120M K 2 Cr 2 O ml K 2 Cr 2 O 7 is required to titrate the FeSO 4. Determine the percentage of iron in the ore. [Fe = 56, Cr = 52, K = 39, O = 16, S = 32] Jawab SEMUA soalan. Answer ALL questions. 5. [16 markah / marks] BAHAGIAN B (50 MARKAH) SECTION B (50 MARKS) (a) Keputusan eksperimen fotoelektrik oleh Einstein adalah berbeza daripada jangkaan teori klasik. Results from photoelectric experiment by Einstein are different from classical theory. Berikan semua postulat yang telah dirumuskan hasil daripada keputusan eksperimen tersebut dan persamaan umum yang menghubungkaitkan fenomena tersebut. Give all the postulates that have been deduced from the experiment and the general equation for the phenomena. (7 markah / marks)

4 SCES1200/ 04 Kirakan nilai fungsi kerja dalam unit ev dan kelajuan elektron yang terpancar apabila plat logam didedahkan kepada radiasi 589 nm. Tenaga kinetik elektron telah ditentukan sebagai 3.37 x J. [Pemalar Planck, h = x Js; kelajuan cahaya, c = 3.0 x 10 8 ms -1 ; jisim elektron, m e = x kg; 1 ev = x J/eV] Calculate the value of work function in ev unit and the velocity of the emitted electron when the metal plate was exposed to a radiation at 589 nm. The kinetic energy of the emitted electrons was determined as 3.37 x J. [Planck constant, h = x Js; velocity of light, c = 3.0 x 10 8 ms -1 ; mass of electron, m e = x kg; 1 ev = x J/eV] (9 markah / marks) 6. [10 markah / marks] (a) Jelaskan sifat-sifat zarah kecil seperti suatu elektron serta tunjukkan persamaan berkaitan yang diterbitkan oleh ahli-ahli saintis berikut: Describe the properties of small particles like an electron and show the related equations derived by scientists below: Louis de-broglie Werner Heisenberg (b) Anggarkan ketakpastian minimum momentum dan ketakpastian kelajuan satu elektron jika ia berada dalam jarak 5 x m. [Pemalar Planck, h = x Js; jisim elektron, m e = x kg] Estimate the minimum uncertainty in momentum and uncertainty of velocity in an electron if it is located within 5 x m. [Planck constant, h = x Js; mass of electron, m e = x kg] (4 markah / marks)

5 SCES1200/ [24 markah / marks] (a) Terbitkan satu persamaan yang menunjukkan hubungan antara ketumpatan suatu gas dengan Persaman Gas Unggul. Derive an equation that shows the relationship between density of a gas and the Ideal Gas Equation. (3 markah / marks) (b) Kirakan ketumpatan gas karbon tetraklorida pada 714 torr dan 125 o C. [Pemalar gas, R = L atm/mol K; 1 atm = 760 torr; C = 12 g/mol; Cl = 35.5 g/mol] Calculate the density of carbon tetrachloride vapor at 714 torr and 125 o C. [Gas constant, R = L atm/mol K; 1 atm = 760 torr; C = 12 g/mol; Cl = 35.5 g/mol] (c) Berikan tiga (3) andaian sebagai asas kepada Model Kinetik Gas. Give the three (3) assumptions as a fundamental to the Kinetic Model of Gases. Terbitkan persamaan min halaju punca kuasa dua molekul-molekul dalam suatu gas. Derive an equation for root mean square speed of molecules in a gas. (3 markah / marks) Kirakan min halaju punca kuasa dua dan min halaju molekul gas CO 2 pada suhu 303 K. [Jisim molar CO 2 = 44 g/mol, R = JK -1 mol -1 ] Calculate the root mean square speed and mean speed of CO 2 at 303 K. [Molar mass CO 2 = 44 g/mol, R = JK -1 mol -1 ] TAMAT END