1781f_05 RJC Promos - 1 RAFFLES JUNIOR COLLEGE 2005...

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Unformatted text preview: 1 RAFFLES JUNIOR COLLEGE 2005 PROMOTIONAL EXAMINATION Level: JC 1 CHEMISTRY Time: 2 hours 03 October 2005 INSTRUCTIONS TO CANDIDATES DO NOT open this booklet until you are told to do so. Write your name and civics tutorial group on the MCQ answer sheet provided as well as on the cover sheet printed on page 8 . Attempt all the questions. At the end of the paper, submit the MCQ answer sheet separately from your answers to section B and section C . Secure section C to the back of section B booklet. INFORMATION FOR CANDIDATES This paper consists of three sections: A , B and C . Section A consists of 15 multiple-choice questions. Answers to this section are to be recorded in soft pencil (type B or 2B is recommended) on the MCQ answer sheet provided. Section B consists of 4 structured questions. Answers to these questions are to be written in the spaces provided on the question paper. Section C consists of 3 free-response questions. Answers to this section are to be written on foolscap paper. Begin your answer to each question on a fresh page of paper. Answers written in pencil for sections B and C are subjected to penalty. You are reminded of the need for good English and clear presentation in your answers. _______ This question booklet consists of 16 printed pages and a piece of graph paper. 2 3 Section A Multiple-Choice Questions (15 marks) There are 15 questions in this section. Answer all questions. For each question, there are four possible answers, labelled A , B , C and D . Choose the one you consider correct and record your choice in soft pencil on the separate MCQ answer sheet. 1. A medicinal tablet for patients suffering from iron-deficiency contains FeSO 4 .7H 2 O. Tablets weighing 3 g were dissolved in water to make 100 cm 3 of solution. 25.0 cm 3 portions of this solution were titrated against a 0.0400 mol dm 3 solution of acidified potassium manganate(V II ). The average titre was 10.50 cm 3 . What is the percentage by mass of iron in the tablets? A 8.5% B 11.6% C 15.7% D 20.1% 2 . The mass spectrum of a compound J has its first two peaks at m/e values of 1 and 14. Two other peaks at m/e values 35 and 37 have relative intensities of 3:1. Which of the following statements is incorrect? A The last peak is observed at m/e value of 89. B The molecule J is trigonal pyramidal in shape. C The molecular ion peaks have relative intensities of 9:6:1. D There are a total of six peaks that correspond to unipositive ions. 3 . Paramagnetism is a phenomenon involving the attraction of a chemical species into a magnetic field. The phenomenon is generally caused by the presence of unpaired electrons . Paramagnetism will be exhibited by A Mg B Zn C Sc 3+ D S 4 . Which of the following pairs of graphs give the same general shape according to the ideal gas law for a fixed mass of gas?...
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1781f_05 RJC Promos - 1 RAFFLES JUNIOR COLLEGE 2005...

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