Chemistry · 2009 · November · Paper 2 · HL · Question paper

8809-6102 14 pages N09/4/CHEMI/HP2/ENG/TZ0/XX+ Tuesday 3 November 2009 (afternoon) CHEMISTRY HIGHER lE vEl Pa PER 2 INSTRUCTIONS TO CANDIDATES • Write your session number in the boxes above. • Do not open this examination paper until instructed to do so. • Section A: answer all of Section A in the spaces provided. • Section B: answer two questions from Section B. Write your answers on answer sheets. Write your session number on each answer sheet, and attach them to this examination paper and your cover sheet using the tag provided. • At the end of the examination, indicate the numbers of the questions answered in the candidate box on your cover sheet and indicate the number of sheets used in the appropriate box on your cover sheet. 2 hours 15 minutes [Personal identifier removed] © International Baccalaureate Organization 2009 88096102 0114 8809-6102 – 2 – N09/4/CHEMI/HP2/ENG/TZ0/XX+ Section a Answer all the questions in the spaces provided. 1. The data below is from an experiment used to determine the percentage of iron present in a sample of iron ore. This sample was dissolved in acid and all of the iron was converted to Fe2+. The resulting solution was titrated with a standard solution of potassium manganate(VII), KMnO4. This procedure was carried out three times. In acidic solution, MnO4 – reacts with Fe2+ ions to form Mn2+ and Fe3+ and the end point is indicated by a slight pink colour. t itre 1 2 3 initial burette reading / cm3 1.00 23.60 10.00 Final burette reading / cm3 24.60 46.10 32.50 Mass of iron ore / g 3 682 10 1. × − concentration of KMno 4 solution / mol dm–3 2 152 10 2. × − (a) Deduce the balanced redox equation for this reaction in acidic solution. ....................................................................... ....................................................................... ....................................................................... ....................................................................... [2] (b) Identify the reducing agent in the reaction. ....................................................................... [1] (c) Calculate the amount, in moles, of MnO 4 – used in the titration.