1778f_03 Promos - -1-RAFFLES JUNIOR COLLEGE 2003 PROMOTION...

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Unformatted text preview: -1-RAFFLES JUNIOR COLLEGE 2003 PROMOTION EXAMINATION CHEMISTRY Level: JCI 15 October 2003 Time: 2 hrs 15 min INSTRUCTIONS TO CANDIDATES 1. Do not open this booklet until you are told to do so. 2. Answer all questions. This paper consists of three sections: Section A, SectionB and Section C. Section Aconsists of 15 multiple-choice questions. For each question, choose the answer you consider to be correct and record your choice with a 2B pencil on the separate answer sheet provided. You are advised not to spend more than 25 minutes on this section. You are to begin with Section A. Answer sheet for Section A will be collected 30 minutes after the start of the examination.Section Bconsists of 6 structured questions. Answers to this section are to be written in the spaces provided on the question paper. Section Cconsists of 3 free response questions. Answers to this section are to be written on writing paper. Start each question on a fresh page.3. Write your answers in ink. Writing in pencil will be subjected to penalty. 4.At the end of the examination, detach Section A. Attach the cover page (page 7) on top of your answers to Sections BandC.INFORMATION FOR STUDENTS The Periodic Tableis provided on page 2. The number of marks is given in brackets [ ] at the end of each question or part of a question. You are reminded of the need for good English and clear presentation in your answers. This question paper consists of 14printed pages. -2--3-SECTION A: MULTIPLE-CHOICE QUESTIONS (15 marks) For questions 1 to 10, four possible answers labelled A, B, Cand D, are given for each question. Choose the one which you consider the most appropriate and record your choice with a 2B pencil on the separate answer sheet provided. 1. 20.0 g of a colourless, liquid commercial bleach containing hydrogen peroxide, H2O2, was diluted in a 250 cm3volumetric flask. 10.0 cm3of the resultant solution required 18.90 cm3of 0.020 mol dm-3acidified potassium manganate(VII) solution, KMnO4, for titration. Calculate the percentage by mass of hydrogen peroxide in the bleach. A0.64 % B1.12 % C2.41 % D4.02 % 2. The number of unipositive fragment ions that can be produced by methane molecules in a mass spectrometer is A3 B4 C5 D6 3. Which one of the following species contains one unpaired electron? ATi4+BCo CNi DCu2+4. Trimethylamine, (CH3)3N, reacts with boron trifluoride, BF3, to form a compound of formula (CH3)3N.BF3. Which of the following illustrates the various descriptions associated with the shapes of these three molecules? Molecular geometry around N in (CH3)3N Number of lone pairs around B in BF3Approximate F-B-F bond angle in (CH3)3N.BF3A trigonal pyramidal 0 109oB tetrahedral 1 109oC tetrahedral 0 120oD trigonal pyramidal 1 120o5. Oxygen is carried by blood as a compound of oxygen and haemoglobin, in which each haemoglobin molecule combines with four oxygen molecules....
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This note was uploaded on 10/12/2010 for the course C 11 taught by Professor Na during the Spring '10 term at Rappahannock Community College.

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1778f_03 Promos - -1-RAFFLES JUNIOR COLLEGE 2003 PROMOTION...

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