DHS_Prelim_P2

CANDIDAT E NAME ____________________________ CG________ DUNMAN HIGH SCHOOL (SENIOR HIGH) YEAR 6 PRELIMINARY EXAMINATION 2009 H1 CHEMISTRY Paper 2 8872/02 22 September 2009 2 hours Additional materials: Answer Paper Data Booklet INSTRUCTIONS TO CANDIDATES 1 Write your name and class on all the work you hand in. 2 Write in dark blue or black pen on both sides of the paper. 3 You may use a soft pencil for any diagrams, graph or rough working. 4 The number of marks is given in brackets [ ] at the end of each question or part question. 5 You may use a calculator. 6 At the end of the exami nation, fasten all your work securely together. Section A FOR EXAMINER’S USE Question Marks 1 /6 2 /8 3 /11 4 /15 Paper 2 Section A /40 5 /20 6 /20 7 /20 Paper 2 Section B /40 Paper 1 /30 Total /110 Grade Answer all questions. Section B Answer tw o questions on separate answer paper. This document consists of 13 printed pages and 1 blank page. [Turn over

2 Section A Answer all the questions in this section in the spaces provided. [Turn over 1 Antimony (Sb), with atom ic number 51 has been known since about 4000BC. Nowadays, its main use is to harden and to strengthen lead alloys. A typical sample of antimony consists of two isotopes and has the following composition by mass: 121Sb, 57.25%, 123Sb, 42.75%. (a) (i) Calculate the relative atomic mass of the antimony sample. (ii) Define the term relative atomic mass. [3] Antimony is produced in two–stage process from the sulphide ore, Sb2S3. The ore is first roasted in oxygen to form the oxide. 2Sb2S3(s) + 9O2(g)  Sb4O6(s) + 6SO2(g) The oxide is then reduced with carbon. Sb4O6(s) + 3C(s)  4Sb(s) + 3CO2(g) (b) Showing your working clearly, calculat e the volume of ca rbon dioxide that would be produced by the processing of 3400 g of Sb 2S3. [Assume that 1 mole of gas occupies 24 dm3 under experimental conditions.] [3] [Total: 6]

3 2 The figure shows a plot of first i onisation energy against atomic number for the elements of atomic number 10 to 18. (The letters are not the chemical symbols for the elements concerned.) (a) Write an equation to define the first ionisation energy of A. [1] (b) Describe the general trend of the ionisation energies from B to I as shown in the graph above. [2] (c) Explain briefly why the first ionisation energy of D is less than C. [2] A First ionisation energy / kJ mol–1 I F H C G E D B Atomic number [Turn over

4 (d) Draw the shape of the orbital from which electron is lost when (i) Element B forms a singly charged ion, (ii) Element H forms a singly charged ion. [2] (e) Give the full electronic configuration of the element labeled F. [1] [Tot