MI_Prelim 2008 H2 Chemistry Paper 1

Class Adm No Candidate Name: This question paper consists of 15 printed pages. [Turn over Preliminary Examinations 2008 Pre-university 3 H2 CHEMISTRY 9746 / 01 Tuesday 9 Sep 2008 1h Additional materials: OMR Data Booklet READ THESE INSTRUCTIONS FIRST 1. Do not turn over this question paper until you are told to do so. 2. Write your name, class and index number in the spaces provided at the top of this page and on any separate answer paper used. 3. Attempt ALL the questions in Section A and B. 4. All answers are to be shaded on the OMR form provided using a 2B pencil. 6. Hand in your answers to the paper (OMR form) and question paper separately. INFORMATION FOR CANDIDATES No extra time will be given for shading of OMR form.

SECTION A (30 MARKS) Answer all questions on the OMR form provided For each question, there are four possible answers, A, B, C and D. Choose the one you consider correct. 1. Lithium forms compounds which are used in dry cells and storage batteries and in high temperature lubricants. It has two naturally occurring isotopes, 6Li (isotopic mass = 6.015121 amu) and 7Li (isotopic mass = 7.016003 amu). Lithium has an atomic mass of 6.9409 amu. What is the percentage abundance of the 6Li isotope? A 7.503% B 46.16% C 86.66% D 92.50% 2. In one experiment, 45.0cm 3 of 0.2moldm-3 aqueous M2+ solution has reacted with 15.0cm3 of 0.1 moldm-3 aqueous acidified potassium dichromate (VI) solution. What is the oxidation state of M after the reaction? A +3 B +4 C +5 D +7 3. Which one of the following is not a redox reaction? A Br2 + SO2 + 2H2O → SO4 2- + 4H+ + 2Br– B SnCl2 + HgCl2 → Hg + SnCl4 C Cu2O + H2SO4 → CuSO4 + Cu + H2O D 2CrO4 2- + 2H+ → Cr2O7 2– + H2O 4. A mixture of 8.0g of a monoatomic gas X and an unknown quantity of diatomic gas Y has a volume of V m 3 at s.t.p. When 20.0g of gas X is added to the mixture, under the same conditions, the volume of the mixture is 2V m3. Calculate the quantity of gas Y in the mixture. [Relative molecular mass: X = 4, Y =1] A 2g B 3g C 5g D 6g 2

5. A new boron hydride, BxHy, has been isol ated. To find its molar mass, you measure the pressure of the gas in a known volume at a known temperature. The following experimental data are collected: Mass of the gas = 12.5mg Pressure of the gas = 3306 Pa Temperature = 25 °C Volume of the flask = 125 mL Which formula corresponds to the calculated mass? A B 2H6 B B 4H10 A B 5H9 A B 6H10 6. Which one of the following is the electron arrangement of the strongest reducing agent? A 1s2 2s2 2p5 B 1s2 2s2 2p6 3s2 C 1s2 2s2 2p6 3s2 3p5 D 1s2 2s2 2p6 3s2 3p6 4s2 7. Which of the following molecules / ions has non-zero dipole moments? A BF 3 B cis-HClC=CHCl C CO 2 D ICl4 - 8. Which one of the equations below represents a reaction that is feasible at all t