Chemistry · 2013 · May · Paper 2 · SL · TZ2 · Question paper

24 pages M13/4/CHEMI/SP2/ENG/TZ2/XX Thursday 16 May 2013 (afternoon) CHEMISTRY STANDARD LEVEL PAPER 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 questions. • Section B: answer one question. • Write your answers in the boxes provided. • A calculator is required for this paper. • A clean copy of the Chemistry Data Booklet is required for this paper. • The maximum mark for this examination paper is [50 marks] . 1 hour 15 minutes © International Baccalaureate Organization 2013 Examination code 2 2 1 3 – 6 1 1 7 [Personal identifier removed] [Personal identifier removed] [Personal identifier removed] – 2 – M13/4/CHEMI/SP2/ENG/TZ2/XX SECTION A Answer all questions. Write your answers in the boxes provided. 1. Iron tablets are often prescribed to patients. The iron in the tablets is commonly present as iron(II) sulfate, FeSO4 . Two students carried out an experiment to determine the percentage by mass of iron in a brand of tablets marketed in Cyprus. Experimental Procedure: • The students took five iron tablets and found that the total mass was 1.65 g. • The five tablets were ground and dissolved in 100 cm3 dilute sulfuric acid, H2SO4 (aq). The solution and washings were transferred to a 250 cm3 volumetric flask and made up to the mark with deionized (distilled) water. • 25.0 cm3 of this Fe2+ (aq) solution was transferred using a pipette into a conical flask. Some dilute sulfuric acid was added. • A titration was then carried out using a 5.00 × 10–3 mol dm–3 standard solution of potassium permanganate, KMnO4 (aq). The end-point of the titration was indicated by a slight pink colour. The following results were recorded. Rough titre First accurate titre Second accurate titre Initial burette reading / cm3 ± 0.05 1.05 1.20 0.00 Final burette reading / cm3 ± 0.05 20.05 18.00 16.80 (This question continues on the following page) 0 2 2 4