HCI H2 Chem 2013 Prelim P2 QP

This document consists of 15 printed pages and 1 blank page. HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 12S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper Additional Materials: Data Booklet 9647/02 18 September 2013 2 hours INSTRUCTIONS TO CANDIDATES 1) Write your name, CT group, centre number and index number clearly in the spaces at the top of this page. 2) Answer all questions in the spaces provided in this Question Paper. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. A Data Booklet is provided. Do not use staples, paper clips, highlighters, glue or correction fluid. You may use a calculator. You are reminded of the need for good English and clear presentation in your answers. For Examiner’s Use 1 / 12 2 / 20 3 / 13 4 / 12 5 / 15 Total / 72 Calculator Model: 567

2 © Hwa Chong Institution 2013 9647 / 02 / C2 Prelim 2013 1 Planning You are provided with a 2.00 mol dm –3 solution of sodium hydroxide and a solution of sulfuric acid of unknown concentration. The enthalpy change of neutralization, Hneut, is the molar enthalpy change for the reaction: H+(aq) + OH–(aq)  H2O(l) A preliminary investigation was carried out to measure the temperature changes, T, when different volumes of the sulfuric acid and sodium hydroxide were reacted together. In one experiment, 10.00 cm 3 of H 2SO4 was reacted with 40.00 cm 3 of NaOH and the temperature change was found to be 11.0 oC. In a second experiment, 20.00 cm 3 of H 2SO4 was reacted with 30.00 cm 3 of NaOH and the temperature change was 18.4 oC. (a) Write a plan to determine the concentration of the sulfuric acid, and a value for the enthalpy change of neutralization, Hneut. Your plan must enable you to plot a graph that includes the data from both of the experiments described above. You may use apparatus normally found in a school laboratory. Your plan should contain the following:  a labelled diagram of the assembled apparatus you would use for measuring the temperature changes, T,  all essential experimental details, including precision of apparatus and volumes of reagents,  a sketch of the graph you expect to obtain, and  an outline of the calculations you would perform to find (i) the concentration, in mol dm–3, of the sulfuric acid (ii) the molar enthalpy change of neutralization, Hneut, in kJ mol– 1 In your calculations, you must clearly define all terms used and simplify your final mathematical expression. You may use letters a, b, … etc, to represent quantities used. 568

3 © Hwa Chong Institution 2013 9647 / 02 / C2