NYJC H2 CHEM P1 QP Prelim

[Turn Over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 27 September 2011 1 hour Additional Materials: Mult iple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, CT and NRIC / FIN on the Answer Sheet in the spaces provided. 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 Multiple Choice Answer Sheet 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. You may use a calculator. This document consists of 14 printed pages.

2 NYJC 2011 H2 Chemistry 9647/01 Prelim Section A For each question in this section, there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1. A sample of 10 dm 3 of polluted air is passed through limewater so that all the carbon dioxide present is precipitated as calciu m carbonate. The mass of calcium carbonate formed is 0.05 g. What is the percentage, by volume, of carbon dioxide in the ai r sample? [A r C, 12.0; O, 16.0; Ca, 40.1] A 0.03 % B 0.05 % C 0.12 % D 0.6% 2. In an experiment, 100 cm 3 of 0.020 mol dm ⎯3 acidified iron (II) sulphate solution is quantitatively oxidized by 50 cm 3 of a solution containing 0.020 mol dm ⎯3 of an oxidizing agent, XO3⎯. What is the final oxidation state of X? A –1 B –2 C +2 D +3 3. A vessel at standard pressure and te mperature contains a mixture of 35Cl2 and 37Cl2. The gaseous mixture occupi es a volume of 5.6 dm 3 and weighs 18 g, calculate the percentage by mass of 35Cl2 in the mixture. A 25 % B 40 % C 50 % D 75 % 4. Equal masses of gaseous N 2, NH3 and N2O are injected into an evacuated vessel to produce a total pressure of 3 atm. How do the partial pressures of N 2, NH3 and N2O compare? A 23 2NN HN OP = P = P B 23 2NN HN OP < P < P C 322NH N N OP < P < P D 223NO N N HP < P < P 5. Which of the following molecules/ ions has the smallest bond angle? A AlH 4⎯ B SO 3 2⎯ C XeF 2 D SF 2

3 NYJC 2011 H2 Chemistry 9647/01 Prelim [Turn Over 6. Cyanamide, NH 2CN, can form a product with boron trifluoride, BF3. Which of the following structures represents the product? A B C D 7. The enthalpy change of solution of magnes ium fluoride is negative (–17.7 kJ mol ⎯ 1) but the enthalpy change of solution of barium fluoride is positive (+3.8 kJ mol⎯1). What conclusion can be drawn from these data? A Magnesium fluoride is soluble in water, but barium fluoride is insoluble. B The hydration energy of the barium ion is numerically greater than that of the magnesium ion. C The lattice energy of barium fluoride is numerically greater than that of the magnesium fluoride. D The lattice energy of barium fluoride is numerically greater than the sum of the hydration energies of the barium and fluoride ions.

4 NYJC 2011 H2 Chemistry 9647/01 Prelim 8. Hydrogen peroxide decomposes in the pres ence of a catalyst according to the equation below. 2H2O2 (aq) → O2 (g) + 2H2O (l) To determine the order of the reaction wit h respect to hydrogen peroxide, a student performed an experiment using the method below. The method is as follows: • Starting the reaction: the reactants H 2O2 and catalyst are mixed and a stop-clock started. • At measured time intervals, samples of the reaction mixture can be extracted. • Noting the time, the reaction is quenched by rapidly adding it to a large beaker o f cold water. • The concentration of the unreacted hydr ogen peroxide remaining in each sample can be found by titrating with standard potassium manganate(VII): Which of the following statements is false ? A The solution is “quenched” to reduce the rate of reaction. B The order of reaction with respec t to hydrogen peroxide can be determined from the graph of volume of potassium manganate(VII) against time, using the half-life method. C The end-point of the ti tration is marked by the disappearance of the pink colour. D Alternatively, the order of the reaction can be studied by measuring the pressure of the system at measured time intervals. 9. The initial rates of the reaction between NO and O 2 were obtained by changing the pressures according to the table below. Experiment No. Initial total pressure / atm Initial pressure of NO / atm Initial rate / atm s⎯ 1 1 5 2 5.4 2 8 2 10.8 3 10 4 43.2 Which of the statements is true about the system above? A The order of the reaction with respect to NO is 1. B The overall order of the reaction is 3. C The rate constant k has units of s ⎯1. D The rate constant k increases as the initial total pressure increases.

5 NYJC 2011 H2 Chemistry 9647/01 Prelim [Turn Over 10. From which of the following reactions can the bond energy of the O—H bond be determined by using only the standard enthalpy change of the reaction? A 2 H (g) + O (g) Æ H 2O (g) B ½ H 2O (l) Æ H (g) + ½ O (g) C H 2 (g) + ½ O2 (g) Æ H2O (g) D H 2O (l) Æ H2O (g) 11. The diagram below is a hydrogen-oxygen fuel cell. Predict the changes in the pH of the so lution around each of the electrode when a current is flowing. Cathode Anode A increase decrease B decrease decrease C decrease increase D increase increase 12. Given the following reaction: A (g) + B (g) Ý 2C (g) + 2D (g) Kp = 2.10 x 102 atm2 An equimolar mixture of A and B is allowed to reach equilibrium at 700 K. Determine the total pressure at equilibrium if the partial pressure of C at equilibrium was found to be 2.00 atm. A 1.28 atm B 4.00 atm C 4.28 atm D 4.56 atm Æ O2 Å H2 1.00 mol dm-3 NaOH Porous electrode

6 NYJC 2011 H2 Chemistry 9647/01 Prelim 13. The numerical value for the solub ility product of calcium phosphate, Ca 3(PO4)2, is 2.07×10⎯33. Determine the solubility of Ca 3(PO4)2. A 2.28 x 10 ⎯ 7 mol dm⎯3 B 1.14 x 10 ⎯7 mol dm⎯3 C 3.42 x 10 ⎯ 7 mol dm⎯3 D 2.91 x 10 ⎯7 mol dm⎯3 14. Which of the following solutions is unable to maintain a fairly constant pH when a small amount of acid is added to it? A 20 cm 3 of 0.1 mol dm⎯3 NH3 with 10 cm3 of of 0.1 mol dm⎯3 H2SO4 B 20 cm 3 of 0.1 mol dm⎯3 NaOH with 20 cm3 of of 0.2 mol dm⎯3 CH3COOH C 0.25 mol KHCO 3 with 0.30 mol K2CO3 D 2-amino-2-methylethanoic acid 15. The graph below shows the first ionisation e nergies of elements in the Periodic Table plotted against increasing atomic number. What are the elements indicated by the letters A, B, C and D? A Group I metals B Group VII halogens C Noble gases D Transition elements A B C D First I.E Atomic number

7 NYJC 2011 H2 Chemistry 9647/01 Prelim [Turn Over 16. The highest oxides of the elements sodium to sulphur are separately added to water. Which of the following diagrams best represents the pH of the solution produced? A B C D 17. Which of the following property of Group II elements decreases from beryllium to barium? A reactivity with water B stability of the carbonates C solubility of hydroxides D second ionisation energy 18. Which of the following are the anions present when chlorine gas is passed through hot concentrated potassium hydroxide. A ClO ⎯, ClO 3⎯ B Cl ⎯, ClO4⎯ C Cl ⎯, ClO⎯ D Cl ⎯, ClO3⎯ SO3 P4O10 SiO2 Al2O3 MgO Na2O pH SO3P4O10Si