JPJC H2 Chemistry P1 QP Prelim

¤ Jurong Pioneer Junior College [Turn Over NAME CLASS 20S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2021 CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice 24 September 2021 1 hour Candidates answer on separate paper. Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and exam index number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C or 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 16 printed pages.

2 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 1 Some isotopes are unstable and undergo nuclear (radioactive) reactions. In one type of reaction, an unstable nucleus assimilates an electron from an inner orbital of its electron cloud. The net effect is the conversion of a proton and an electron into a neutron. Which of the following describes this type of reaction? A 11C o 12C B 111I o 111Te C 76Br o 75Br D 76Kr o 75Br 2 Figure 1 shows the first six ionisation energies of an element P. Figure 2 shows the second ionisation energies of eight consecutive elements (including P). Figure 1 Figure 2 With reference to Figure 2, which of the options, A, B, C or D, corresponds to the second ionisation energy of element P? 3 Which of the following has the largest bond angle? A SiCl4 B SO2 C IF2— D CH3+ Ionization Energy/ kJ mol-1 Electron removed 1 2 3 4 5 6 Second Ionization Energy/ kJ mol-1 Atomic number A B C D

3 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 [Turn Over 4 Molecular dimerisation can be described as the process in which two identical molecules combine to give a single product. Examples of dimers are N2O4 and (CH3CO2H)2. Which of the following descriptions about the above dimers is incorrect? A Hydrogen bonds hold the CH3CO2H molecules together in the dimer. B There is one nitrogen-nitrogen single bond in N2O4. C (CH3CO2H)2 is a non-planar molecule. D The nitrogen-oxygen bonds in N2O4 are of different length. 5 Naturally-occurring silicon is a mixture of three isotopes, 28Si, 29Si and 30Si. The relative atomic mass of silicon is 28.109. What could be the relative abundance of each of the three isotopes? A 91.1% 28Si, 7.9% 29Si and 1.0% 30Si B 92.2% 28Si, 4.7% 29Si and 3.1% 30Si C 95.0% 28Si, 3.2% 29Si and 1.8% 30Si D 96.3% 28Si, 0.3% 29Si and 3.4% 30Si 6 A tube filled with 50 cm3 of methane and 150 cm3 of oxygen at room temperature was inverted over a vessel containing KOH (aq) as shown in the diagram. The hydrocarbon was ignited for the following reaction to take place. CH4 + 2O2 → CO2 + 2H2O When the setup is cooled to room temperature, at which level will the liquid be? A 50 cm3 B 100 cm3 C 150 cm3 D 200 cm3 KOH(aq)

4 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 7 An experiment was conducted to determine the efficiency of the heating of a can of water using a spirit burner. The following data were recorded: Mass of ethanol burnt = m g Change in temperature of water = ΔT oC You are also given that: Relative molecular mass of ethanol = 46.0 Enthalpy change of combustion of ethanol = –1371 kJ mol−1 Specific heat capacity of water = c J g−1 K−1 Which expression below gives the efficiency of this heating process? A 300 T 46.0 100%1371 1000 c m uu 'u uuu B T4 6 . 0100%300 1371 1000 mcuu 'u uuu C 300 T 46.0 100%1371 c m uu 'u uu D 1371 1000100%300 T 46.0 m c uu uuu 'u thermometer can containing 300 g of water burner containing ethanol

5 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 [Turn Over 8 In 1944, T. Ellingham published plots of 'G against temperature T for a number of reactions. Today, such plots are called Ellingham diagrams. An Ellingham diagram for three reactions involving the oxidation of C and CO is shown below. Which of the following shows correctly the three reactions corresponding to I, II and III in the above Ellingham diagram? I II III A 2CO + O2 o 2CO2 C + O2 o CO2 2C + O2 o 2CO B 2C + O2 o 2CO 2CO + O2 o 2CO2 C + O2 o CO2 C C + O2 o CO2 2CO + O2 o 2CO2 2C + O2 o 2CO D 2C + O2 o 2CO C + O2 o CO2 2CO + O2 o 2CO2

6 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 9 The graphs below show how the percentage of gaseous products present at equilibrium vary with temperature and pressure. Which one of the following reactions could the graph represent? A N2O4(g) 2NO2(g) ΔH = +57 kJ mol‒1 B H2(g) + I2(g) 2HI(g) ΔH = +53 kJ mol‒1 C N2(g) + 3H2(g) 2NH3(g) ΔH = ‒92 kJ mol‒1 D C(s) + O2(g) 2CO(g) ΔH = ‒99 kJ mol‒1 10 At a temperature T K, 0.80 mol of SO2 and 0.40 mol of O2 were introduced into a 10 dm3 vessel and allowed to come to equilibrium. 2SO2(g) + O2(g) ⇌ 2SO3(g) 'H < 0 The graph below shows the variations in the amounts of SO2 and SO3 in the system with time. A change was made to the system at time t. Which of the following statements are correct? 1 A catalyst was added at time t 2 Temperature was decreased at time t 3 An inert gas was added at constant volume at time t 4 The value of Kc before time t is 14.4 % products at equilibrium pressure (T + 10) oC T oC

7 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 [Turn Over A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4 11 At body temperature of 37 oC, Kw has a value of 2.4 x 10–14. What is the concentration of OH– if the pH of blood is 7.4 under these conditions? A 7.00 x 10‒7 B 2.51 x 10‒7 C 6.03 x 10‒7 D 3.98 x 10‒8 12 A 0.100 mol dm3 solution of lead(II) nitrate is added, with stirring, into an equal volume of a solution containing a mixture of Cl, Br, and I ions, each with the same concentration of 1.0 x 102 mol dm3. Given the following data: Compound Numerical value of Ksp (at 25 °C) Lead(II) chloride 1.7 x 10‒5 Lead(II) bromide 6.6 x 10‒6 Lead(II) iodide 9.8 x 10‒9 Which one of the following statements is correct? A No precipitate will form. B Only PbI2 precipitate will form. C A mixture of PbI2 and PbBr2 precipitates will form. D All three precipitates, PbI2, PbBr2, and PbCl2, will form. 13 When the gases dinitrogen tetroxide and nitrogen monoxide are mixed in a 1:2 ratio, the two gases slowly react to form the blue compound dinitrogen trioxide according to the following equilibrium. N2O4 (g) + 2NO (g) 2N2O3 (g) ΔH = –26 kJmol-1 The forward and backward rate constants are given as k1 and k-1 respectively. What happens to the equilibrium constant Kp, k1, and k-1 if at equilibrium, the temperature of the reaction mixture is increased? k1 k–1 Kp A Increases Decreases Increases B Unchanged Increases Unchanged

8 ¤ Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2021 C Increases Increases Decreases D Decreases Increases Decreases 14 Consider one mole of ideal gas at a given pr