SAJC H2 Chem 2012 Prelim P1 QP

1 ST ANDREW’S JUNIOR COLLEGE JC2 Preliminary Examinations Chemistry Higher 2 9647/01 Paper 1 Multiple Choice 19 September 2012 1 hour Additional Materials: Multiple Choice Answer Sheet, Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. There are 40 questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Chose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. This document consists of 22 printed pages including this page. [Turn Over

2 [Turn Over Section A For each question there are four possible answers, A , B, C and D. Choose the one you consider to be correct. 1. Group I and Group II ionic hydrides react with water. H- + H2O ® OH- + H2 In an experiment, 1 g of a sample of an ionic hydride is dissolved in excess H 2O. The resulting solution required 24.00 cm3 of a 2.0 mol dm -3 HCl solution for complete neutralisation. What is the formula of the hydride? A LiH B NaH C MgH2 D CaH2 2. Which species is oxidised and which species is reduced in the following reaction? 4TiCr2O4 + 8Rb2CO3 + 7O2 à 8Rb2CrO4 + 2Ti2O3 + 8CO2 Species oxidised Species reduced A Chromium only Carbonate ion only B Chromium only Carbonate ion and oxygen C Chromium and titanium Oxygen only D Chromium and titanium Carbonate ion and oxygen

3 [Turn Over 3. The graph below shows how pressure varies with temperature when 1 mole of helium is heated in an enclosed volume. p T/ o C0 Similar relationshi p between pressure and temperature was examined for 1 mole of gaseous XY2 which dissociates according to the following equation. XY2 (g) X (g) + Y2 (g) ∆H > 0 Which graph best represents how pressure varies with temperature of the gas? A p T/ o C0 C p 0 T / oC B p 0 T / oC D p 0 T / oC

4 [Turn Over 4. Which of the following particles has a half-filled p subshell after losing two electrons? A Ga- B As2+ C Se- D Te+ 5. Which of the following isomers is likely to have the highest boiling point? A O B O C OH D OH 6. In which of the following reactions is the H –N–H bond angle in ammonia smaller than that in the product? A 2NH3 (l) + 2Na (s) ® 2NaNH2 (s) + H2 (g) B NH3 (g) + HCl (g) ® NH4Cl (s) C 2NH3 (g) ® H2N–NH2 (l) + H2 (g) D 2NH3 (g) + O2 (g) ® 2NH2OH (l)

5 [Turn Over 7. When water vaporises, 51.6 kJ mol -1 of heat enthalpy is required. What is the entropy change when 54 g of water boils at 1 atm? A + 138 J K-1 B + 415 J K-1 C + 516 J K-1 D + 1548 J K-1 8. Ellingham diagrams are plots of ∆G against temperature, T. An Ellingham diagram for two reactions involving the oxidation