DHS_2008 Prelim - H1 Chemistry Paper 2

This question paper consists of 12 printed pages and 0 blank page. [Turn over CANDIDATE NAME ____________________________ CLASS________ DUNMAN HIGH SCHOOL (SENIOR HIGH) YEAR 6 PRELIMINARY EXAMINATION 2008 H1 CHEMISTRY Paper 2 8872/02 17 September 2008 2 hours Candidates answer Section A on the Question Paper Additional Materials: Data Booklet Answer Paper INSTRUCTIONS TO CANDIDATES 1 Write your name and class on this question paper and on all the work you hand in. 2 A Data Booklet is provided. 3 You may use a calculator. 4 The number of marks is given in brackets [ ] at the end of each question or part question. 5 At the end of the examination, fasten all your work securely together with this question paper. Section A 6 Answer all questions. 7 Write your answers in the spaces provided on the question paper. Section B 8 Answer two questions on separate answer paper. FOR EXAMINER’S USE Section A Section B Total % Question 1 2 3 4 5 6 7 Marks 14 9 8 9 20 20 20 [80]

2 © DHS 2008 8872/02 [Turn over Section A Answer all the questions in this section in the spaces provided. 1(a) The graph below shows the trend in a particular property of Period 3 elements. (i) Label on the y–axis of the graph, the property represented. (ii) Briefly explain the trend of this property. [4] (b) One student, Mr Piah, is given three aqueous solutions of the oxides of three Period 3 elements. He adds the indicator, thymol blue, to the three unknown solutions separately and noted the colours of the solutions. (i) With reference to the pH range and colour of thymol blue indicator, identify each of these solutions in the spaces provided below. pH range pH < 1.2 2.8 < pH < 8.0 pH > 9.6 colour of thymol blue red yellow blue solution colour observed identity of oxide 1 green 2 blue 3 red Ionic radius /nm • • • • • • proton number | 11 | 13 | 14 | 15 | 16 | 17 | 18 | 12 •

3 © DHS 2008 8872/02 [Turn over (ii) Briefly outline the reaction of these oxides with water, supporting your answer with appropriate equations. [4] (c) One of the clearest ways in which atomic pr operties influence chemical behavior appears in the diagonal relationships of elements. One such example is beryllium and aluminium, from Group II and III respectively. Their oxides show similar chemical behaviour towards acids and bases. Write equations to show the reactions of beryllium oxide with the following: NaOH (aq) : BeO + 2HCl Æ BeCl2 + H2O HCl (aq) : [2]

4 © DHS 2008 8872/02 [Turn over (d) Nickel is a silvery–white metal that takes on a high polish. It is a transition metal and is hard and ductile. Naturally occurring nickel is composed of five stable isotopes. A mass spectrometer provides the following information about the relative abundance of the five isotopes. i