2019 JPJC Prelim H2 Chem P2 QP

 Jurong Pioneer Junior College [Turn Over NAME CLASS 18S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2019 CHEMISTRY 9729/02 Higher 2 Paper 2 Structured Questions 17 September 2019 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, class and exam index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a HB pencil for any diagrams, graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 17 2 17 3 19 4 22 Penalty (delete accordingly) Bond linkages –1 / NA Total 75 This document consists of 18 printed pages.

2  Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2019 Answer all the questions. 1 Copper, a transition element, and iodine , a Group 17 halogen, are both shiny crystalline solids. The crystal structures of copper and iodine are both face centred cubic. Figure 1.1 shows the arrangement of the particles in this type of crystal lattice. Figure 1.1 In Figure 1.1, the particles present are represented by . For Examiner’s Use (a) (i) What type of particles is present in the copper crystal? State the interactions within the crystal. Particles : ............................................................................................ Interactions : ............................................................................................ [1] (ii) What type of particles is present in the iodine crystal? State the interactions within the crystal. Particles : ............................................................................................ Interactions : ............................................................................................ [1] (b) Explain why copper is malleable and ductile. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ [1]

3  Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2019 [Turn Over (c) Give an example of another physical property that is present in one of the above solids but absent in the other. Explain. For Examiner’s Use ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ [2] (d) A sample of copper contains the two isotopes 63Cu and 65Cu only. An experiment is conducted to find the relative atomic mass of this s ample and is found to be 63.9. (i) Explain why the value found is not a whole number. .................................................................................................................. [1] (ii) Suggest why the relative atomic mass stated above differs from the value obtained from the Periodic Table. .................................................................................................................. .................................................................................................................. [1] (e) When separate beams of 63Cu2+ and 127I− are passed through an electric field in Figure 1.2, they behave differently. On Figure 1.2 , sketch the paths taken by beams of 63Cu2+ and 127 I− in the presence of electric field, given that the angle of deflection of the Cu2+ beam is 7.0 . Figure 1.2 [2]

4  Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2019 (f) Group 17 halogens Cl2, Br 2 and I2 are often used as oxidising agents in chemical reactions. Describe, using relevant Evalues from the Data Booklet , the trend in the reactivity of the halogens, Cl2, Br2 and I2 as oxidising agents. For Examiner’s Use ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ [2] (g) In acidic solutions, H 2O2 is one of the most powerful oxidising a gents known and is stronger than the halogens. H2O2 reacts with aqueous iodine as shown in equation 1. equation 1 I2(aq) + 5H2O2(aq)  2IO3 (aq)+ 2H+(aq) + 4H2O(l) E cell = +0.57 V (i) Write the half–equations for the above reaction between H2O2 and I2. Hence, use relevant data from the Data Booklet to calculate E(IO3/I2). [2]

5  Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2019 [Turn Over (ii) Draw a fully labelled diagram of the electrochemical cell you would set up in order to measure the cell potential of reaction 1 under standard conditions. In your answer, you should include the following:  describe th e measurement you would make determine the cell potential,  polarity of electrodes and,  direction of electron flow. For Examiner’s Use [4] [Total: 17]

6  Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2019 2 Table 2.1 lists the solubility of the Group 2 carbonates at 25 C. Table 2.1 Group 2 element, M Solubility of MCO3 / mol dm3 Mg 1.87  104 Ca 6.16  105 Sr 1.05  105 For Examiner’s Use (a) By considering the relationsh ip between Hsoln, lattice energy and Hhyd, explain why the solubility of Group 2 carbonates, decreases down the group. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ [2] (b) Selective precipitation is a technique of separating two or more ions from a solution by adding a suitable reagent that selectively precipitates one ion over the other ions. A student carried out a selective precipitation experiment by slowly adding, dropwise, volumes of aqueous Sr(NO 3)2 solu