IJC H1 CHEM P2

INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION 2 in preparation for General Certificate of Education Advanced Level Higher 1 CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY Paper 2 Structured and Free Response Questions Section A: Structured Candidates answer Section A on the Question Paper Section B: Free Response Additional Materials: Writing Papers Data Booklet 8872/02 24 September 2009 2 hours READ THESE INSTRUCTIONS FIRST Write your index number, name and civics group on all the work you hand in. Write in dark blue or black pen. You may use pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A: Structured Questions (40m) Answer all questions in the space provided. For Examiner’s Use Section A 1 10 2 10 3 9 4 11 Significant Figures Total 40 Section B: Free Response Questions (40m) Answer two questions on separate writing papers. You are advised to show all working in calculations. You are reminded of the need for good English and clear presentation in your answers. You are reminded of the need for good handwriting. Your final answers should be in 3 significant figures. You may use a calculator. The number of marks is given in brackets [ ] at the end of each question or part question. At the end of the examination, fasten all your work securely together. This document consists of 17 printed pages and 1 blank page. Innova Junior College [Turn over

PRELIM 2  INNOVA 8872/02/09 [Turn over 2 For Examiner’s Use Section A Answer ALL questions on the space provided. 1 The purity of iodates ( VII) can be estimated by adding an acidified solution of potassium iodide and titrating the iodine produced with aqueous sodium thiosulphate. In one such analysis, a 0.100 g sample of impure sodium iodate ( VII), Na 5IO6, was dissolved in water and treated with an excess of acidified KI. IO6 5- + 7I- + 12H+ 4I2 + 6H2O The iodine liberated required 22.0 cm 3 of 0.100 moldm-3 sodium thiosulphate, Na 2S2O3 to reach its end point. Calculate the purity of the sodium iodate (VII). (a) (i) Write a balanced ionic equation for the reaction between thiosulphate and iodine. (ii) Calculate the number of moles of iodine liberated. (iii) Calculate the number of moles of pure Na 5IO6 required to produce the iodine in part (ii). (iv) Calculate the mass of pure Na 5IO6 in the sample. (v) Calculate the purity of the sodium iodate (VII). [5]

PRELIM 2  INNOVA 8872/02/09 [Turn over 3 For Examiner’s Use (b) In the 1980s, there was an international agreement to destroy all stockpiles of mustard gas, C lCH2CH2SCH2CH2CH2Cl. When this substance contacts the moisture in eyes, nasal passages, and skin, the OH groups of water replace the C l atoms and create high local concentrations of hydrochloric acid, which cause severe blistering and tissue destruction. C Given the balanced equation, lCH2CH2SCH2CH2Cl + 2 H2O  HOCH2CH2SCH2CH2OH + 2 HCl Use the table of average bond energies given below to calculate ∆Hr for this reaction. bond average bond energy / kJ mol –1 C – C 350 C – H 410 C – Cl 340 C – O 360 H – Cl 431 O – H 460 S – C 272 S – H 347 [3]

PRELIM 2  INNOVA 8872/02/09 [Turn over 4 For Examiner’s Use (c) It is observed that when a beam of 23 is passed through an electric field, it gives an angle o f deflection of 1.5°. Calculate the angle of deflection for a sample consisting when it passes through the same electric field. 8 + 92U + 2 206 82 Pb [2] [Total:10] 2 Benzoic acid, C 7H6O2 (or C 6H5COOH), is a colourless crystalline solid and the simplest aromatic carboxylic acid. The name is der ived from gum benzoin, which was for a long time the only source for benzoic acid. When dissolved in organic solvent, it is capable of dimerisation. A dimer is a chemical or biologica l entity consisting of two structurally similar subunits called monomers. (a) (i) Identify the type of bonding between the benzoic acid molecules during dimerisation. Type of Bonding: ………………………………………………… (ii) Draw a diagram to illustrate your answer in (i). [3]

PRELIM 2  INNOVA 8872/02/09 [Turn over 5 For Examiner’s Use (b) During aromatic substitution, the position of the incoming group, is determined by the nature of the substituent already present in the ring. If Y is an electron-withdrawing group, the incoming group will be in position 3. If Y is an electron-releasing group, the incoming group will be mostly in position 4. Using nitration as an example, The following table lists some electron-withdrawing and electron-donating substituents. electron-withdrawing substituents electron-donating substituents – NO2 – NH2 – COOH – CH2Br Benzoic acid is an important precursor for the synthesis of many other organic substances. Study the reaction schemes below involving benzoic acid and its derivatives. (i) Use the above information to draw rele vant structural formulae of compounds P and Q in the boxes provided. [2] CH3COOH CH2Br Step 1 Benzoic acid Methylbenzene Nitration Step 2 Br2 FeBr3 Compound P Compound Q

PRELIM 2  INNOVA 8872/02/09 [Turn over 6 For Examiner’s Use (ii) Give reagent(s) and condition(s) for each of the steps 1 and 2. Step Reagent(s) and Condition(s) 1 2 [2] (iii) Draw the structural formula of the product formed when benzoic acid is refluxed with ethanol in the presence of concentrated sulphuric acid. [1] (iv) Explain if 3-nitrobenzoic acid is more or less acidic than benzoic acid. COOH NO2 3-nitrobenzoic acid ………………………………………………………………..…………………............ ………………………………………………………………..…………………............ ………………………………………………………………..…………………............ ………………………………………………………………..…………………............ ………………………………………………………………..…………………........[2] [Total: 10]

PRELIM 2  INNOVA 8872/02/09 [Turn over 7 For Examiner’s Use 3 Lovastatin is a member of the drug class of statins, used for lowering cholesterol in those with hypercholesterolemia and so preventing cardiovascular