2012 JJC H1 Prelim P2

1 Jurong Junior College 8872/02/Prelim 2012 [Turn over q JURONG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CANDIDATE NAME CLASS EXAM INDEX NUMBER CHEMISTRY 8872/02 Paper 2 Structured Questions 27 August 2012 2 hours Candidates answer Section A on the Question Paper. Additional Materials: Answer Paper Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, class and 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 soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions. Section B Answer two questions on separate answer paper. A Data Booklet is provided. Do not write anything on the Data Booklet. 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 Section A B6 B7 B8 Total This document consists of 14 printed pages.

2 Jurong Junior College 8872/02/Prelim 2012 [Turn over Section A Answer all questions in this section in the spaces provided. 1. (a) (i) On the following diagrams, plot points to show the variation in the named property of some Period 3 elements. Your points should indicate for each element, the relative position of first ionisation energy/ ionic radius with respect to other elements. The point for sulfur has already been plotted in each case. (ii) Briefly explain the following trends: the difference in first ionisation energy between phosphorus and sulfur. …...……………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… the trend in ionic radius from silicon to chlorine. …...……………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [5] (b) (i) Describe what you would observe when a few drops of water is added to phosphorus(III) chloride, PCl3. Write an equation for this reaction. …………………………………………………………………………………… …………………………………………………………………………………… Ionic radius Si P S Cl first ionisation energy Si P S Cl

3 Jurong Junior College 8872/02/Prelim 2012 [Turn over 1. (b) (ii) When microwave radiation is passed through phosphorus( III) chloride, PCl3, at low pressure, a new chloride of phosphorus, A, is formed. A contains 69.6% by mass of chlorine and 30.4% by mass of phosphorus, and its Mr is 200. Calculate the empirical and molecular formulae of A. (iii) Assuming phosphorus and chlorine show their typical valencies, draw the displayed formula of A, showing all bonds and lone pairs. [5] [