MJC_H2_CHEM_P2_ANS

Name ________________________ Class: ___________ Reg Number: _____ MERIDIAN JUNIOR COLLEGE JC2 Preliminary Examination Higher 2 ___________________________________________________________________ CHEMISTRY 9647/02 Paper 2 Structured Questions 19 September 2011 2 hours Additional Materials: Data Booklet. ___________________________________________________________________ INSTRUCTIONS TO CANDIDATES Write your name, class and register number in the spaces provided at the top of this page. Write your calculator brand and model/number in the box provided above. Answer all questions in the spaces provided on the question paper. All working must be shown clearly. INFORMATION FOR CANDIDATES This document consists of 20 printed pages. FOR EXAMINER’S USE Q1 / 12 Q2 / 17 Q3 / 21 Q4 / 10 Q5 / 12 Total / 72 The number of marks is given in brackets [ ] at the end of each question or part question. You are reminded of the need for good English and clear presentation in your answers. Calculator Model / No.

2 Answer all questions in the space provided. 1 Planning (P) You are provided with solutions FB 3 , FB 4 and FB 5 . FB 3 and FB 4 are either 1.0 mol dm –3 nitric acid or 2.0 mol dm –3 ethanoic acid whereas FB 5 is 1.0 mol dm –3 sodium hydroxide. You are to plan experiments that will enable you to identify the solution that matches each of FB 3 and FB 4 , hence, calculate /uni2206Hneutralisation for the reaction between ethanoic acid and sodium hydroxide. You are provided with the following apparatus: –10 ° C to 110 ° C thermometer, 100 cm 3 beaker, 50 cm 3 measuring cylinder The measuring cylinder should be rinsed thoroughly before each use. (a) (i) When determining the identity of the two acids lis ted above, the independent variable is the nature or strength of acids the dependent variable is temperature change (ii) Plan an experiment to find which of the solutions i s 1.0 mol dm –3 nitric acid and which is 2.0 mol dm –3 ethanoic acid. Your plan must identify the acids solely based on t he change in temperature. Mathematical processing of the tempera ture change is thus not required. Your experiment(s) must use only the solutions and apparatus above.

3 Your plan should give a step by step description of the method including: • the apparatus used for measurement • appropriate volumes of reagents • how you would measure the various variables [4] Method 1. Measure 25 cm 3 of FB 5 using the 50 cm 3 measuring cylinder, and transfer it into the 100 cm 3 beaker. 2. Measure and record the initial temperature in th e 100cm 3 beaker using a thermometer. 3. Measure 25 cm 3 of FB 3 using the 50 cm 3 measuring cylinder. 4. Carefully transfer the FB 3 into the 100 cm 3 beaker, stir, and record the highest temperature reached. 5. Repeat steps 1-4 b