2021 YIJC Prelim P1 QP

©YIJC [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CG INDEX NO CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 16 September 2021 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and class 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 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 16 printed pages.

2 ©YIJC [Turn over 1 A 1.00 g alkane D was burnt in an excess of oxygen, and the gases that were produced were first passed through a U-tube containing phosphorus pentoxide and another U-tube containing NaOH(s) as shown in the diagram. The phosphorus pentoxide U -tube increased in mass by 1.55 g, and the NaOH(aq) bottle increased in mass by 3.03 g. All volumes were measured at room temperature and pressure. What is the molecular formula of the alkane D? A CH4 B C2H5 C C2H6 D C4H10 2 Use of the Data Booklet is relevant to this question. What do the ions 36S2 and 37Cl have in common? A Both ions have more electrons than neutrons. B Both ions have the same electronic configuration. C Both ions contains the same number of nucleons. D 36S2 has a smaller angle of deflection than 37Cl in an electric field. 3 Boyle’s law states that at constant temperature, the volume of a fixed mass of gas is inversely proportional to its pressure. Which of the following statements shows application of Boyle’s law? 1 Human lungs, inhalation and exhalation. 2 Spraying paint from a can. 3 Working of hot air balloon. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only Oxygen gas used oxygen gas Phosphorous pentoxide NaOH(s) pellets Alkane D

3 ©YIJC [Turn over 4 Carmine is a red colorant extracted from the bodies of dead female insects, used in food colouring and lipsticks. The proposed structure of carmine is as shown. The Al+ ion is situated in the centre of a planar arrangement of numbered oxygen atoms. Which of the following descriptions of the bonds between Al+ and the numbered O atoms is most likely to be correct? O atoms numbered 1 O atoms numbered 2 A co-ordinate co-ordinate B co-ordinate ionic C ionic co-ordinate D ionic ionic

4 ©YIJC [Turn over 5 The table shows the boiling point of some halogenoalkanes. compound boiling point/ °C CH3CH2Cl 12.3 CH3CH2Br 34.8 CH3CH2I 70.0 Which of the following correctly explains the difference in the boiling point? 1 the electronegativity difference between the halogen and carbon increases from C−Cl to C−I 2 the strength of permanent dipole -permanent dipole attraction increases from C−Cl to C−I 3 the strength of instantaneous dipole-induced dipole attraction increases from CH3CH2Cl to CH3CH2I 4 the bond energy of C−X bond decreases from C−Cl to C−I A 1 and 2 only B 2 and 4 only C 3 only D 4 only 6 The radioactive decay of element X is a first-order reaction. It take 16 days for element X to decay to 25% of its initial value. What fraction of element X would remain after 800 days? A 1 210 B 1 250 C 1 280 D 1 2100

5 ©YIJC [Turn over 7 The Boltzmann distribution of kinetic energies for the following equilibrium N2O4(g) ⇌ 2NO2(g) H = +57 kJ mol1 is shown graphically below as temperature is increased. Which statements can be drawn from the graph? 1 At all energies, the number of molecules of N2O4 of a given value increases. 2 The maximum of the curve lowers and shifts to the right. 3 The reaction is first order with respect to [N2O4]. 4 The number of molecules with energies equal or greater than Ea increases. A 1, 2 and 3 only B 1 and 2 only C 2 and 4 only D 3 and 4 only 8 Methanol can be synthesised from hydrogen and carbon monoxide using a suitable catalyst at 480 K and a pressure of 3 x 106 Pa. 2H2(g) + CO(g)  CH3OH(g) H = –90.6 kJ mol–1 The reaction mixture reached equilibrium under the above conditions. The graph below shows how the pressure of CH3OH varied with time. What could be the changes made to the system at t1 and t2? t1 t2 A CH3OH was added Temperature was decreased B CO was added Temperature was increased C Temperature was decreased CO was added D Temperature was increased CH3OH was added number of molecules energy Ea = activation energy T1 T2 T2 > T1 Pressure of CH3OH time t1 t2 t3

6 ©YIJC [Turn over 9 A quantity of ethanol was burned underneath a copper can containing 400 g of water at 30 oC. The temperature of the water rose to 85 oC after the complete combustion of 5 g of ethanol (Mr = 46.0). The efficiency of heat transfer to the water will not be 100% after taking into considerations the heat capacity of the copper can and heat loss to surroundings. Given that the specific heat capacity of water is 4.2 J g‒1 K‒1 and the enthalpy change of combustion of ethanol is ‒1367 kJ mol‒1, what is the efficiency of heat transfer to the water? A 27% B 39% C 62% D 96% 10 Which equation corresponds to the enthalpy change stated? A 2Al3+(g) + 3O2−(g) → Al2O3(s) 2ΔH olattice energy(Al2O3(s)) B H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l) ΔH oneutralisation (H2O(l)) C CaCl2(s) → Ca2+(aq) + 2Cl−(aq) ΔH osolution(CaCl2(s)) D 1 4P4(s) + 5 2O2(g) → 1 4P4O10(s) ΔH oformation(P4O10(s)) 11 Calcium reacts with water to form calcium hydroxide and hydrogen. Ca(s) + 2H2O(l)  Ca(OH)2(s) + H2(g) The standard enthalpy change for this reaction can be measured in the laboratory. What further information is needed in order to calculate the standard enthalpy change of formation of calcium hydroxide, Hfo? 1 Hfo for H2O(I) 2 Hfo for H2(g) 3 Hatomisationo for Ca(s) 4 first and second ionisation energies of Ca(s) A 1, 3 and 4 only B 2, 3 and 4 only C 3 and 4 only D 1 only

7 ©YIJC [Turn over 12 Use of the Data Booklet is relevant to this question. Water undergoes selfionisation according to the equation: H2O (l) H+(aq) + OH– (aq) At 60 °C, the ionic product of water, Kw, has the value of 9.5 x 1014 moI2 dm6. Which statement concerning water at 60°C is correct? A The pH is 6.51. B [OH] = 4.75 x 107 mol dm3 C The water is slightly acidic. D Heating water from 25 °C to 60 °C causes water to ionise to a lesser extent. 13 Values of two solubility products are given Ksp value at 25 °C CaCO3 8.7  109 CaF2 4.0  10−11 Solid CaCO3 is shaken with water. The remaining solid is filtered off, leaving behind a saturation solution X. Drops of F(aq) are added to solution X until CaF2 just precipitates. Which row of the table is correct? [Ca2+(aq)] in solution X / mol dm−3 [F(aq)] when CaF2 just precipitates / mol dm−3 A 9.33  10−5 6.55  10−4 B 9.33  10−5 9.67  10−3 C 2.15  10−4 6.55  10−4 D 2.15  10−4 4.31  10−4 14 Which factors deter