2024 NYJC H1 Chem 8873 P1

[Turn over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CHEMISTRY 8873/01 Paper 1 Multiple Choice 16 September 2024 1 hour 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 tutor’s name 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 H1 Chemistry 8873/01 NYJC J2/24 PX 1 Use of the Data Booklet is relevant to this question. 20 g of ethanol and 30 g of propanoic acid are heated under reflux, 22 g of ethyl propanoate is obtained. What is the yield of the ester? A 50% B 53% C 56% D 60% 2 Use of the Data Booklet is relevant to this question. 0.144 g of an aluminium compound A react with excess water to produce a gas. This gas burns completely in oxygen to form water and 72 cm3 of CO2 only. What is the molecular formula of compound A? [All volumes were measured at room temperature and pressure.] A Al2C3 B Al3C4 C Al4C3 D Al5C3 3 In this question, assume only V and Zn change oxidation numbers. Two moles of VO 2+ ions react with one mole of zinc atoms in the presence of dilute acid. The products include Zn 2+ ions and an ion, Y. Ion Y contains vanadium. What is ion Y? A VO3− B VO+ C VO2+ D VO22+

3 H1 Chemistry 8873/01 NYJC J2/24 PX [Turn over 4 A single 32P nucleus can be produced when a single 32S nucleus reacts with particle X. In the process a proton is emitted. What is particle X? A a deuteron, B an electron C a neutron D a proton 5 Which statement about the electrons in a n aluminium atom at ground state is correct? A Electrons are present in three different energy levels. B There are more electrons in s orbitals than there are in p orbitals in total. C The occupied orbital of lowest energy is circular. D The e lectron from the occupied orbital with the highest energy is removed first during ionisation. 6 In which process does bond angle decrease at the relevant central atom? 1 when ice melts 2 oxidation of SO2 to SO3 3 oxidation of a secondary alcohol by acidified KMnO4 4 dimerisation of aluminium chloride A 4 only B 1 and 3 only C 1 and 4 only D 2 and 3 only 7 When two liquids are mixed, heat may be evolved if intermolecular bonds formed are stronger, than those broken, even if there is no chemical reaction. Which pair of liquids, when mixed, will give out heat? A CH2Cl2 and (CH3)2CO B CHCl3 and C6H14 C CCl4 and (CH3)2CO D CCl4 and CH3CH2OH

4 H1 Chemistry 8873/01 NYJC J2/24 PX 8 Three substances W, X and Y have physical properties as shown. substance melting point / oC electrical conductivity W 1410 slight X 3650 good Y – 70 poor What could be the correct identities of W, X and Y? W X Y A Si C(graphite) SiCl4 B Si C(diamond) SiO2 C C(diamond) C(graphite) SiO2 D C(graphite) C(diamond) SiCl4 9 Calcium(I) chloride, CaC l, does not exist as a stable compound but its lattice energy can be estimated. What is the predicted order of increasing magnitude of lattice energy of CaC l, CaCl2 and MgCl2? A MgCl2, CaCl2, CaCl B CaCl2, MgCl2, CaCl C CaCl, MgCl2, CaCl2 D CaCl, CaCl2, MgCl2 10 Which statement about the standard enthalpy change of formation of carbon dioxide is correct? A It is equal to twice the bond energy of the C=O bond. B It is equal to the standard enthalpy change of combustion of carbon. C It is the same for carbon dioxide produced from graphite and from diamond. D It is the energy change when one mole of carbon dioxide is formed from its constituent elements in their standard states at 273 K and 1 bar.

5 H1 Chemistry 8873/01 NYJC J2/24 PX [Turn over 11 50.0 cm3 of 2.00 mol dm −3 H2SO4 is added to 100 cm 3 of 1.00 mol dm −3 NaOH in an insulated vessel. Both solutions are at a temperature of 20.0 °C before mixing. On mixing, the temperature rises and the highest temperature recorded is 29.0 °C. Assume that no energy is lost to the surroundings and the density of the mixture is 1 g cm−3 and its specific heat capacity is 4.18 J g−1 K−1. What is the value of the enthalpy change of neutralisation as determined from this experiment? A –56.4 kJ mol−1 B –28.2 kJ mol−1 C +28.2 kJ mol−1 D +56.4 kJ mol−1 12 The diagram shows a Boltzmann distribution of the energies of gaseous molecules and the activation energies, Ea, of a reaction with and without a catalyst. Which statement about this distribution curve is correct? A If the temperature of the gas is increased, the maximum of the curve becomes higher. B If the temperature of the gas is increased, the maximum of the curve moves to the left. C The fraction of molecules that react in the presence of a catalyst is shown by . D The fraction of molecules that react in the absence of a catalyst is shown by . proportion of molecules with energy, E molecular energy, E Ea1 Ea2 0 0

6 H1 Chemistry 8873/01 NYJC J2/24 PX 13 Which changes can be used to measure the rates of chemical reactions? 1 the decrease in concentration of a reactant per unit time 2 the rate of appearance of a product 3 the increase in total volume of gas per unit time at constant pressure A 1 only B 1 and 2 C 2 and 3 D 1, 2 and 3 14 The equation for the formation of ammonium chloride is shown. NH3(g) + HCl(g) ⇌ NH4Cl (g) H = −314 kJ mol–1 Which diagram shows the correctly label led reaction pathway diagram for the decomposition of ammonium chloride? A B C D energy energy energy energy progress of reaction progress of reaction progress of reaction progress of reaction NH4Cl NH4Cl NH3 + HCl NH3 + HCl NH3 + HCl NH3 + HCl NH4Cl NH4Cl

7 H1 Chemistry 8873/01 NYJC J2/24 PX [Turn over 15 The Contact process to convert SO 2 into SO3 takes place at a pr essure between 100 kPa and 200 kPa and at a temperature between 400 C and 450 C. A catalyst is used. 2SO2(g) + O2(g) Ý 2SO3(g) H < 0 Which statement is correct? A V2O5 catalyst is added to increase the equilibrium yield of the reaction. B The higher temperature will increase the yield of the reaction. C The higher pressure has no effect on the position of equilibrium. D A catalyst and a high temperature will increase the rate of reaction. 16 Nitrosyl chloride, NOCl, is produced when NO and Cl2 are reacted. The equation is shown. 2NO(g) + Cl2(g) Ý 2NOCl(g) 2.32 mol of NO and X mol of Cl2 are mixed in a sealed container of volume 1.00 dm3 at a temperature of 573 K. The system is allowed to reach equilibrium. The equilibrium mixture contains 1.77 mol of NOCl. The equilibrium constant, Kc, for the reaction at 573 K is 2807. What is the value of X? A 0.886 mol B 0.889 mol C 1.770 mol D 1.771 mol

8 H1 Chemistry 8873/01 NYJC J2/24 PX 17 The equation shows that H2(g) and I2(g) react to form an equilibrium mixture. H2(g) + I2(g) Ý 2HI(g) H < 0 A mixture containing equal amounts of H 2(g) and I2(g) is made at temperature T1 and the composition of the mixture is monitored. A graph of the results is shown. The experiment is repeated at a lower temperature, T2.