MI H2 Chem 2012 Prelim P1 QP

Class Adm No Candidate Name: This question paper consists of 16 printed pages. [Turn over] 2012 Preliminary Examination II Pre-university 3 H2 CHEMISTRY 9647 / 01 Paper 1 20 Sept 2012 1 hour Additional Materials: OMR Data Booklet READ THESE INSTRUCTIONS FIRST INSTRUCTIONS TO CANDIDATES 1. Do not turn over this question paper until you are told to do so. 2. Write your name, class and admission number in the spaces provided at the top of this page and on the OMR provided. 3. Answer ALL questions and shade the correct answers on the OMR provided using a soft pencil. 4. No extra time will be given for shading. 5. Hand in the question paper and the OMR separately. INFORMATION FOR CANDIDATES Marks will not be deducted for wrong answers; your total score will be the number of correct answers given. FOR EXAMINER’S USE TOTAL (40 marks)

2 Answer all questions on the OMR form provided (40 Marks) For each question, there are four possible answers, A, B, C and D. Choose the one you consider correct. 1 Zn reacts with VO3 - ions to give Vn+. 3.9 g of Zn was required to react completely with 40.0 cm3 of 1.0 mol dm-3 of KVO3. What is the value of n? A 1 C 3 B 2 D 4 2 In which of the following pairs do the species have different shapes? A AlCl3 and CO3 2- B NH4 + and CH4 C NH3 and H 3O+ D SeF4 and SO4 2- 3 The following graph shows how ionic radius changes across Period 3 for seven elements. A The sharp increase in ionic radius between the 4th and 5th element is due to an increase in the number of principal quantum shells. B There is a decrease in ionic radius for the first 4 elements in Period 3 due to decreasing shielding effect. C There is a decrease in ionic radius for the last 3 elements due to decreasing proton to electron ratio. D The first 4 elements form anions and hence have lower ionic radii than the last 3 elements which form cations. 11 12 13 14 15 16 17 Atomic Number Unknown PropertyIonic radius

[Turn over 3 4 In which of the following reactions is the acid acting as an oxidant? A KBr + H3PO4  HBr + KH2PO4 B MgO + H2SO4  MgSO4 + H2O C 12HClO4 + P4O10  6Cl2O7 + 4H3PO4 D Cu + 4HNO3  Cu(NO3)2 + 2H2O + 2NO2 5 A 1 dm3 flask containing helium at 2 kPa pressure is connected (at constant temperature) to a 2 dm3 flask containing neon at 1 kPa pressure. What is the final pressure after connection? A ସ ଷ kPa B ଷ ଶ kPa C ହ ଷ kPa D 2 kPa 6 The use of the Data Booklet is relevant to this question. Phosphorus, P4, has the following molecular structure: Imagine that nitrogen were to form a similar molecule N4 shown in the reaction below: 2N2(g)  N4(g) What would be the value of ΔH (in kJ mol–1) for the above reaction? A 1028 B 1348 C 1954 D 2628

7 Which gas shows the greatest deviation from ideal gas behavior? A HCl B He C CH4 D N2 8 The use of the data booklet is relevant to this question. In many areas, tap water is slightly acidic due to dissolved will not be dissolved by tap water containing carbon dioxide? A Cr B Cu 9 Which of the following mixtures is A H2O/OH- B H2PO4 -/HPO4 2- 10 Which of the following pairs of solutions would form an acidic buffer when mixed? A HCN and NaCN B HNO3 and NaNO3 C NaOH and NaCl D HCl and NaOH 11 Bleaching solutions are manufactured by dissolving chlorine gas in sodium hydroxide solution to give the following reaction. Cl2 (g) + Users are warned not to mix the bleach with other cleaning solutions to prevent evolution of hazardous chlorine gas. Which of the following actions will lead to gas? A Addition of water to bleach B Mixing of an alkali with bleach C Shaking bleach with table salt, NaC D Subjecting bleach to high pressure 4 Which gas shows the greatest deviation from ideal gas behavior? The use of the data booklet is relevant to this question. In many areas, tap water is slightly acidic due to dissolved carbon dioxide. Which metal will not be dissolved by tap water containing carbon dioxide? C Fe D Pb Which of the following mixtures is not an acid/conjugate base pair? C NaH/Na D NH3/NH2 - Which of the following pairs of solutions would form an acidic buffer when mixed? Bleaching solutions are manufactured by dissolving chlorine gas in sodium hydroxide solution to give the following reaction. (g) + 2OH- (aq) OCl- (aq) + Cl- (aq) + H2O ( Users are warned not to mix the bleach with other cleaning solutions to prevent evolution of hazardous chlorine gas. Which of the following actions will lead to Addition of water to bleach Mixing of an alkali with bleach Shaking bleach with table salt, NaCl Subjecting bleach to high pressure carbon dioxide. Which metal Which of the following pairs of solutions would form an acidic buffer when mixed? Bleaching solutions are manufactured by dissolving chlorine gas in sodium hydroxide O (l) Users are warned not to mix the bleach with other cleaning solutions to prevent evolution liberation of chlorine

12 Given that, Equilibrium I: C (s) + O Equilibrium II: C (s) + ½ O Equilibrium III: CO (g) + ½ O What is the numerical Kc A 3 2 B 3 2 13 The rate of removal of the pain reaction with a rate constant, How long will it take for 6.25% of the paracetamol ingested to remain in the body? A 2.7 hours B 10.6 hours 14 Sulfates of Group II metals exist as crystalline form as follows: MgSO4.7H2 Which one of the following accounts for this trend in hydration? A The atomic radius of B The ionic character of these sulfates increases down the group. C The ionisation energy of the elements decreases down the group. D The radius of the cation increases down the group. 15 X is a mixture of two compounds acid, a colour gas is evolved and some, but not all of the mixture dissolves. Which one of the following mixtures could be A Ba(NO3)2 and Ca(OH) B Ag2SO4 and CaCO3 C CaCO3 and MgSO4 D Ca(OH)2 and MgCO 5 C (s) + O 2 (g) CO2 (g) Kc1 = 3 C (s) + ½ O2 (g) CO (g) Kc2 = 2 : CO (g) + ½ O 2 (g) CO2 (g) Kc = ? c value for the Equilibrium III? C 2 3 D 2 3 The rate of removal of the pain -killing drug paracetamol from the body is a first order reaction with a rate constant, k, of 0.26 h1. How long will it take for 6.25% of the paracetamol ingested to remain in the body? C 8.1 hours D 13.5 hours metals exist as crystalline form as follows: 2O CaSO4.2H2O SrSO4 Which one of the following accounts for this trend in hydration? The atomic radius of the elements increases down the group. The ionic character of these sulfates increases down the group. The ionisation energy of the elements decreases down the group. The radius of the cation increases down the group. is a mixture of two compounds. When X is treated with an excess of dilute hydrochloric acid, a colour gas is evolved and some, but not all of the mixture dissolves. Which one of the following mixtures could be X? and Ca(OH)2 and MgCO3 [Turn over killing drug paracetamol from the body is a first order How long will it take for 6.25% of the paracetamol ingested to remain in the body? BaSO4 The ionisation energy of the elements decreases down the group. is treated with an excess of dilute hydrochloric acid, a colour gas is evolved and some, but not all of the mixture dissolves.

6 16 A yellow precipitate of cadmium(II) sulfide is formed when H2S is passed into an aqueous solution of cadmium(II) ions, Cd2+. This precipitate is also obtained in the presence of dilute hydrochloric acid but not in the presence of concentrated hydrochloric acid nor in excess potassium chloride. Which explanation accounts for all these observations? A The presence of a high concentration of H+ (aq) suppresses the ionisation of H2S (aq). B The concentration of S2- (aq) is reduced by the formation of SCl4 2- (aq). C CdS (s) is insoluble in concentrated HCl (aq). D Cd2+ (aq) ions react with Cl- (aq) to form the complex ion [CdCl4]2- (aq). 17 A current of 2.0 A is used to plate Ni(s) from 500 cm3 of a 1.00 mol dm-3 Ni2+(aq) solution. What is the concentration of Ni2+(aq) after 3.0 hours? A 0.39 mol dm-3 B 0.46 mol dm-3 C 0.78 mol dm-3 D 0.89 mol dm-3 18 Which one of the following statements is co