ACJC Chemistry H2 P1 Prelims

ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examinations CHEMISTRY 9746/01 Higher 2 Paper 1 Multiple Choice 26 August 2008 1 hour Additional Materials: Multiple Choice Answer Sheet Soft clean eraser Soft pencil (type B or HB is recommended) D a t a B o o k l e t READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, Centre number and candidate number on the answer sheet in the spaces provided unless this has been done for you. There are forty questions in this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate answer sheet. Read the instructions on the answer sheet very carefully. 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 17 printed pages. 9746/01/Prelim/08 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2008 Department of Chemistry [Turn over

2 Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 In an experiment, Mn2+ ions are oxidised by S2O8 2− to form MnO4 − according to the following equation. 2Mn2+(aq) + 5S2O8 2−(aq) + 8H2O(l) → 2MnO4 −(aq) + 10SO4 2−(aq) +16H+(aq) What volume of 0.100 mol dm -3 solution of acidified Mn 2+ is required to reduce completely 25.0 cm3 of 0.200 mol dm-3 of Na2S2O8 solution? A 10 cm3 B 20 cm 3 C 30 cm 3 D 50 cm 3 2 In an experiment, 50 cm 3 of a 0.1 mol dm –3 solution of a metallic salt reacted exactly with 25 cm3 of 0.1 mol dm-3 aqueous sodium sulphite. The half equation for the oxidation of the sulphite ion is shown below. SO3 2–(aq) + H2O(l) → SO4 2–(aq) + 2H+(aq) + 2e– If the original oxidation number of the metal in the salt was +3, what would be the final oxidation number of the metal? A 0 B +1 C +2 D +4 3 10 cm 3 of a pure hydrocarbon was completely burned in 80 cm 3 of oxygen (an excess) at 425K. After cooling to room temperature, the volume of the gaseous mixture decreased by 105 cm 3 to 55 cm3. A further reduction of 40 cm3 was observed when the residual gas was passed through calcium hydroxide. All gas volumes were measured at the same temperature and pressure. What is the formula of the hydrocarbon? A C 2H6 B C 3H8 C C 4H10 D C 5H12 4 Which of the following electronic configurations represents an element that forms a simple ion with a charge of -3? A 1s2 2s2 2p6 3s2 3p1 B 1s2 2s2 2p6 3s2 3p3 C 1s2 2s2 2p6 3s2 3p6 3d1 4s2 D 1s2 2s2 2p6 3s2 3p6 4s2 3d3 © ACJC 2008 9746/01/Prelim/08 [Turn over

3 5 Use of the Data Booklet is relevant to this question. The graph shows the logarithm of the ionisation energy for the outermost ten electrons in an atom of an element X. Which of the following could be X? A silicon B magnesium C neon D phosphorous log IE 105 Number of electrons 6 Which one of the following species is not planar? A XeF 4 B ICl4 - C C2Cl4 D PCl4 + 7 Hydrogen trioxide, H2O3, is an unstable compound but can be isolated in small quantities. Carbon suboxide, C3O2, is a foul-smelling gas obtained by fully dehydrating propan-1,3-dioic acid. Which of the following shows reasonable Lewis structures for these two molecules? Hydrogen trioxide Carbon suboxide A HO O OH OC C C O B OH O HO OC C C OOO C HO O OH OC C C O D OH O HO OC C C O © ACJC 2008 9746/01/Prelim/08

4 8 Trimethoprim (TMP) is used for the treatment and prevention of urinary tract infections, traveller's diarrhoea, respiratory and middle ear infections. It has the following structure: Trimethyoprim (TMP) N N C H H NH2 NHH OCH3 CH3O C H H HO Z yx w In which sequence are the bond angles quoted in decreasing order? A x > y > w > z B x > y > z > w C y > z > w > x D y > w > z > x 9 The diagram shows the electrolysis of a concentrated aqueous solution containing both copper(II) ions and sodium ions Which metal is deposited at the negative electrode and why? metal deposited reason A copper copper is less reactive than sodium B copper copper is more reactive than hydrogen C sodium copper is less reactive than hydrogen D sodium copper is more reactive than sodium © ACJC 2008 9746/01/Prelim/08 [Turn over

5 10 When a solution of concentrated sodium carboxylate is electrolysed, the equation for the reaction is 2RCO2Na + 2H2O R-R + 2CO 2 + 2NaOH + H2 Which statement regarding the electrolysis is incorrect? A Hydrogen is liberated at the cathode. B R-R is liberated at the cathode. C Carbon dioxide is liberated at the anode. D The solution around the cathode turns red litmus blue. 11 Ethyl ethanoate undergoes hydrolysis in water in the presence of HCl which catalysed the reaction. Which of the following graphs would confirm that the rate of reaction is first order with respect to HCl? A B C D Rate of reaction Rate of reaction [HCl] 0 [HCl] 0 Rate of reaction Rate of reaction [HCl] 0 [HCl] 0 12 An equimolar mixture of A and B at an initial total pressure of 2 atm was allowed to reach equilibrium. The equation for the reaction is: A(g) + 2B(g) 2C(g) At equilibrium the total pressure was reduced to 1.8 atm. What is the numerical value of K p? A 0.010 B 0.383 C 0.556 D 0.729 © ACJC 2008 9746/01/Prelim/08

6 13 The following graph shows the pH changes when a 0.10 mol dm-3 solution of A is added to 20.0 cm3 of 0.10 mol dm-3 of sulphuric acid. Which statement regarding the titration is correct? A Point X has maximum buffering capacity. B At point Y the salt is hydrolysed to give an acidic solution. C Point Z has maximum buffering capacity. D The A is a strong base. pH Volume of A / cm3 Z Y X 1 7 20 40 60 13 14 The value of the solubility product of strontium hydroxide is 3.0 x 10-4. The mass of strontium hydroxide required to prepare 1 dm3 of saturated solution is A 3.0 x 10-4 x 121.6 g B 3.0 x 10-4/2 x 121.6 g C 410 3.0−× x 121.6 g D 3 4 4 10 0 . 3−× x 121.6 g 15 Which species represented by the following formulae has the largest radius? A P3- B Cl - C Ar D K+ © ACJC 2008 9746/01/Prelim/08 [Turn over

7 16 Which statement concerning the third period elements sodium to argon and their compounds is not correct? A The elements become more electronegative from sodium to chlorine. B The atomic radius of the elements decrease from sodium to chlorine. C Aluminium oxide is the only oxide which is insoluble in water. D The highest oxidation state is shown by chlorine. 17 The graph below show the variation in the molar enthalpy change of vapourisation, ΔH vap for 8 consecutive elements in the Periodic Table, all with atomic number ≤ 20. What can be deduced from the above graph? A Element A forms amphoteric oxides. B Element C is in the same group as boron in the Periodic Table. C Element F exists as diatomic molecules. D Element G forms an oxide which is acidic in aqueous solution. A G C B D E F H ΔHvap / kJ mol-1 Atomic number © ACJC 2008 9746/01/Prelim/08

8 18 Beryllium dichloride, BeCl2, reacts with methylamine, CH3NH2 to form a compound. Which one of the statements is incorrect? A The compound is formed from 1 mole of BeC l2 and 2 m