NYJC H2 Chemistry P1 Prelim

NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 26 September 2014 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. Write your name, class and tutor’s name on the Answer Sheet in the spaces provided unless this has been done for you. There are forty questions on 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 you 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 22 printed pages and 0 blank page. [Turn over

2 H2 Chemistry 9746/01 NYJC J2/14 PX Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 0.02 mol of CxHyNO2 was burned in excess of oxygen as shown by the equation below. CxHyNO2 + aO2  xCO2 + NO2 + 2 y H2O The gases that were produced were first passed through a U -tube containing phosphorus pentoxide and then bubbled through 0.25 mol of NaOH(aq). The equations illustrating the reactions of the gases with NaOH(aq) are as shown below. CO2 + 2NaOH  Na2CO3 + H2O 2NO2 + 2NaOH  NaNO2 + NaNO3 + H2O The phosphorus pentoxide U -tube increased in mass by 1.15 g and the excess NaOH required 40.00 cm3 of 0.875 mol dm3 H2SO4 for complete reaction. What is the ratio of x:y? A 2:3 B 4:3 C 4:7 D 8:7 2 Which of these samples of gas contains half the number of atoms as 1 g of hydrogen (Mr : H2, 2)? A 22 g of carbon dioxide (Mr : CO2, 44) B 8 g of methane (Mr : CH4, 16) C 20 g of neon (Mr : Ne, 20) D 8 g of ozone (Mr : O3, 48)

3 H2 Chemistry 9746/01 NYJC J2/14 PX [Turn over 3 Which transition metal ion in the following species has one more elec tron in the third quantum shell than in the second quantum shell? A [Cu(EDTA)]2- B [Fe(H2O)5(SCN)]2+ C [Ni(NH2CH2CH2NH2)3]2+ D [VO(C2O4)2(H2O)]2 4 Which of the following statements about the properties associated with ionic and covalent bonds is correct? A The only coval ent compounds with high melting points are those in which hydrogen bonds occur. B Any covalent compound that contains both oxygen and hydrogen in its molecule forms hydrogen bonds. C Ionic bonds and covalent bonds cannot both occur in the same compound. D Ionic compounds differ from metals in that ionic compounds do not conduct electricity in the solid state. 5 For a fixed mass of an ideal gas, which of the following graphs does not have the same general shape as the graph of V/T against T plotted at constant P? ( = density of the gas) A p/ against V (at constant T) B PV against  (at constant T) C T against P (at constant T) D T against V (at constant P)

4 H2 Chemistry 9746/01 NYJC J2/14 PX 6 The standard enthalpy change of vapourisation, ∆Hvap, is defined as the enthalpy change when one mole of a substance changes from liquid state to the gaseous state under standard conditions. Given the following energy cycle, what is the entropy change when 108 g of water vapourises at 373 K? A −2139 J K−1 B −713 J K−1 C +713 J K−1 D +2139 J K−1 7 Oxidation of atmospheric SO2 can be catalysed by NO2 as shown in the following equation. SO2(g) + ½O2(g) SO3(g) The proposed mechanism for the oxidation process is as follows: Step 1: SO2 + NO2  SO3 + NO Step 2: NO + ½O2  NO2 Which of the following statement is not correct? A Both SO2 and SO3 can cause acid rain. B NO2 is a free radical. C NO is not a homogenous catalyst. D Nitrogen atom exhibits variable oxidation states in this reaction. C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O(g) 2CO2(g) + 3H2O(l) ∆H1 = −1235 kJ mol−1 ∆H2 = −1368 kJ mol−1 ∆H3 NO2(g)

5 H2 Chemistry 9746/01 NYJC J2/14 PX [Turn over 8 Consider the following equilibrium, N2O4(g) ⇌ 2NO2(g) ∆H = +57 kJ mol−1 A certain amount of N 2O4 was placed in a closed vessel and allowed to reach equilibrium. Two changes were made to the equilibrium system at t1 and t2. Using the graph above, what are the changes made at t1 and t2? t1 t2 A [NO2] increase [N2O4] decrease B Pressure increase [N2O4] decrease C Volume of vessel decrease Temperature increase D Catalyst added Temperature increase time Concentration / mol dm−3 t1 t2 0 [N2O4] [NO2]

6 H2 Chemistry 9746/01 NYJC J2/14 PX 9 The Haber process is an industrial reaction to produce ammonia from nitrogen and hydrogen. N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = −92 kJ mol−1 Typical conditions used in the Haber process are 200 atm and 450 oC. When a mixture of 2.0 mol of nitrogen, 6.0 mol of hydrogen and 4.0 mol of ammonia is placed in a 2 dm 3 closed vessel and allowed to reach equilibrium at 450 oC, half of the ammonia was decomposed. The Boltzmann distribution diagram of Haber process is shown below. Which of the following statement is correct? A The Kc value is 7.32 × 10−3 mol−2 dm6 at 500 oC. B The percentage yield of ammonia can be increased when ammonia is immediately removed once it is produced. C When a heterogeneous catalyst is added, the shaded area decreases. D When a heterogeneous catalyst is added, the position of equilibrium shifts to the right, producing more ammonia. Number of particles Energy Ea

7 H2 Chemistry 9746/01 NYJC J2/14 PX [Turn over 10 Phosphate buffers are commonly used in biological chemistry research. H3PO4 ⇌ H2PO4 – + H+ pKa1 = 2.0 H2PO4 – ⇌ HPO4 2– + H+ pKa2 = 6.7 HPO4 2– ⇌ PO4 3– + H+ pKa3 = 12.0 A phosphate buffer with pH 7.4 was prepared using NaH 2PO4 and Na 2HPO4 solutions. The total hydrogen phosphates concentration ([HPO4 2–] + [H 2PO4 –]) of the buffer was 0.3 mol dm–3. What are the concentrations of NaH2PO4 and Na2HPO4 used to create this buffer? [NaH2PO4] / mol dm–3 [Na2HPO4] / mol dm–3 A 0.23 0.07 B 0.07 0.23 C 0.10 0.50 D 0.05 0.25 11 Which of the following 0.10 mol dm –3 solutions are arrang ed in order of increasing pH? A HCl < CH3CO2Na < (CH3)4NCl < NH3 B HCl < (CH3)4NCl < CH3CO2Na < NH3 C NH3 < CH3CO2Na < (CH3)4NCl < HCl D NH3 < (CH3)4NCl < CH3CO2Na < HCl 12 Use of the Data Booklet is relevant to this question. Which of the following pairs of reagents can have a feasible reaction? A Cl– and I2 B H2O2 and SO4 2– C V2+ and Sn4+ D Fe2+ and VO2+

8 H2 Chemistry 9746/01 NYJC J2/14 PX 13 A current of 0.44 A is passed through a solutio n of ruthenium nitrate causing reduction of the metal ion. After 25 minutes, 0.345 g of ruthenium h as been deposited. What is the formula of ruthenium nitrate? A RuNO3 B Ru(NO3)2 C Ru(NO3)4 D Ru(NO3)6 14 The graph below shows how a property of the elements sodium to chlorine varies with proton number. Which of the following best represents the property? A atomic radius of their elements B first ionisation energy of their elements C melting points of their chlorides D melting points of their oxides 15 When 1.0 g of a Group II nitrate was heated at a certain temperature, the gas es liberated at r.t.p. had a total volume of 0.4 dm3. What is the identity of the group II nitrate? A Mg(NO3)2 B Ca(NO3)2 C Sr(NO3)2 D Ba(NO3)2 x x x x x x x 11 12 13 14 15 16 17 proton number

9 H2 Chemistry 9746/01 NYJC J2/14 PX [Turn over 16 Group VII elements and their compounds exhibit trends in properties. Which of these properti