Chemistry · 2016 · November · Paper 3 · HL · Question paper

N16/4/CHEMI/HP3/ENG/TZ0/XX [Personal identifier removed] Higher level Paper 3 © International Baccalaureate Organization 2016 42 pages 1 hour 15 minutes Tuesday 15 November 2016 (morning) 8816 – 6103 Instructions to candidates • Write your session number in the boxes above. • Do not open this examination paper until instructed to do so. • Answers must be written within the answer 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 [45 marks]. Section A Questions Answer all questions. 1 – 2 Section B Questions Answer all of the questions from one of the options. Option A — Materials 3 – 10 Option B — Biochemistry 11 – 16 Option C — Energy 17 – 22 Option D — Medicinal chemistry 23 – 29 44EP01 – 2 – Section A Answer all questions. Write your answers in the boxes provided. 1. In order to provide safe drinking water, a water supply is often treated with disinfectants, which aim to inactivate disease-causing bacteria in the water. To compare the effectiveness of different disinfectants, a CT value is used as a measure of the dosage of disinfectant needed to achieve a certain level of inactivation of specific bacteria. CT value (mg min dm−3) = C (mg dm−3) × T (min) concentration contact time of disinfectant with water (a) The table below compares the CT values of different disinfectants necessary to achieve 99 % inactivation of two types of bacteria, listed as A and B. Disinfectant CT value / mg min dm−3 for 99 % inactivation of bacteria Bacterium A Bacterium B Hypochlorous acid, HOCl 4 × 10−2 8 × 10−2 Hypochlorite ion, OCl− 9.2 × 10−1 3.3 Chlorine dioxide, ClO2 1.8 × 10−1 1.3 × 10−1 Monochloramine, NH2Cl 64 94 (i) Deduce the oxidation state of chlorine in the following disinfectants. [1] HOC l: .......................................................................... C lO2: .......................................................................... (This question continues on the following page) N16/4/CHEMI/HP3/ENG/TZ0/XX 44EP02