2019 HCIS IB2 HL Prelim Paper 2

− 1 − Turn over PRELIMINARY EXAMINATION International Baccalaureate 2 Chemistry Higher level Paper 2 Tuesday 3 September 2019 2 hour 15 minutes Candidate name Candidate session number Class Instructions to candidates  Write your candidate name and session number in the boxes above.  Do not open this examination paper until instructed to do so.  Answer all questions.  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 [90 marks]. 23 pages © Hwa Chong International School 2019 For Examiner’s Use Q1 /15 Q2 / 15 Q3 / 9 Q4 / 10 Q5 / 15 Q6 / 9 Q7 / 17 Total / 90

− 2 − Answer all questions. Write your answers in the boxes provided. 1. 9.74 tonnes of magnesium is needed to react with 1.60 x 10 2 tonnes of impure titanium (IV) oxide, TiO2, ore. All the titanium is completely extracted from the sample of impure ore. The following are reactions involved in the extraction process: Step 1: TiO2 + C + 2Cl2  TiCl4 + CO2 Step 2: TiCl4 + 2Mg  Ti + 2MgCl2 (1 tonne = 106 g) (a) Write an overall equation for extraction of titanium from TiO2. [1] …………………………………………………………………………………………………………………..… (b) Calculate the amount, in moles, of TiO2 present in the sample of impure ore. [1] ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. (c) Calculate the mass, in tonnes, of TiO2 in the sample of impure ore. [2] ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. (d) Calculate the percentage by mass of TiO2 in the sample. [1] ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. (This question continues on the following page)

− 3 − Turn over (Question 1 continued) (e) (i) Titanium (IV) oxide , TiO 2, is a solid, however titanium (IV) chloride , TiC l4, is a liquid at room temperature. Suggest a reason for this difference between the two compounds, in terms of structure and bonding. [2] ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. (ii) Titanium (IV) chloride is relatively stable in aqueous solutions. However, it dissolves in concentrated hydrochloric acid to form an acidic solution of the hexachlorotitanate (IV) complex ion. Draw the structure of the complex ion