ASR 2020 J2Prelim H2Chem P1 QP

ASRJC JC2 PRELIM 2020 9729/01/H2 [Turn over ANDERSON SERANGOON JUNIOR COLLEGE 2020 JC 2 PRELIMINARY EXAMINATION CHEMISTRY 9729/01 Paper 1 Multiple Choice 23 September 2020 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 and class on the Answer Sheet in the spaces provided. 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. Multiple Choice Answer Sheet Write your name, class and NRIC / FIN number, including the reference letter. Shade the NRIC / FIN number. Exam Title: JC2 Preliminary Exam Exam Details: H2 Chemistry / Paper 1 Date: 23/09/2020

2 ASRJC JC2 PRELIM 2020 9729/01/H2 1 Beams of charged particles are deflected by an electric field. In an experiment, protons are deflected by an angle of +15º. In another experiment, under identical conditions, particle A is deflected by an angle of –5º. What could be the composition of particle A? protons neutrons electrons A 1 2 2 B 3 3 2 C 3 3 4 D 4 5 1 2 50 cm 3 of a 0.10 mol dm –3 solution of a metallic salt was found to react exactly with 25.0 cm3 of 0.10 mol dm–3 aqueous sodium sulfite. In this reaction, the sulfite ion is oxidised as follows. SO32–(aq) + H2O(l)  SO42–(aq) + 2H+(aq) + 2e What is the new oxidation number of the metal in the salt if its original oxidation number was +3? A +1 B +2 C +4 D +5 3 Which particle would, on losing two electrons, have a half–filled p subshell? A Ga– B Se– C Te+ D As2+

3 ASRJC JC2 PRELIM 2020 9729/01/H2 [Turn over 4 The successive ionisation energies (I.E.) of two elements, B and C, are shown below. I.E. / kJ mol–1 1st 2nd 3rd 4th 5th 6th 7th 8th B 1000 2252 3357 4556 7004 8496 27107 31719 C 578 1817 2745 11577 14842 18379 23326 27465 What is the likely formula of the compound formed when B and C reacts together? A B2C3 B B3C2 C BC3 D B3C 5 Molecular dimerisation can be described as the process in which two identical molecules combine to give a single product. Examples of dimers are: Al2Cl6, 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 Each aluminium atom is surrounded by four chlorine atoms in Al2Cl6. C All the nitrogen–oxygen bonds in N2O4 are of equal length. D Al2Cl6 is a planar molecule. 6 Which of the following observations can be explained by intermolecular hydrogen bonding? 1 Ammonia (NH3) has a higher boiling point than methane (CH4). 2 Water has a lower density at 0 °C than at 25 °C. 3 Formation of H3O+ from water. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only

4 ASRJC JC2 PRELIM 2020 9729/01/H2 7 Melphalan is a drug used in chemotherapy. When dissolved in blood, the decrease in its concentration has a constant half–life of 90 minutes. A 100 mg melphalan tablet is dissolved in 4.0 dm3 blood. What is the concentration of melphalan in the blood six hours later? A 1.56 mg dm−3 B 3.13 mg dm−3 C 12.5 mg dm−3 D 25.0 mg dm−3 8 Hydrogen peroxide slowly decomposes at room temperature. 2H2O2  2H2O + O2 Two experiments were performed to study the effects of adding lead( IV) oxide on the decomposition of 1.5 mol dm–3 hydrogen peroxide at constant temperature. Experiment 1: 20 cm3 of hydrogen peroxide. Experiment 2: 20 cm3 of hydrogen peroxide and 1.0 g of lead(IV) oxide. At the end of the experiment 2 the mixture was filtered and 1.0 g of lead( IV) oxide was recovered. Which row is correct? value of rate constant activation energy A equal in experiment 1 and 2 higher in experiment 1 B equal in experiment 1 and 2 higher in experiment 2 C higher in experiment 2 higher in experiment 1 D higher in experiment 2 higher in experiment 2 volume of O2(g) / cm3 0 time / s experiment 2 experiment 1

5 ASRJC JC2 PRELIM 2020 9729/01/H2 [Turn over 9 The values for the standard enthalpy change of combustion of hydrogen and the standard enthalpy change of formation of hydrogen peroxide are 285.8 kJ mol1 and 187.8 kJ mol1 respectively. What is the standard enthalpy change for this reaction? 2H2O(l) + O2(g)  2H2O2(l) A 98 kJ mol1 B 196 kJ mol1 C +98 kJ mol1 D +196 kJ mol1 10 In vehicles such as cars, internal combustion engines convert the chemical energy in fuels into kinetic energy. The following reaction takes place in an internal combustion engine. 2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(g) What are the signs for H, S and G for the above reaction? H S G A +  + B + +  C  + + D  + 

6 ASRJC JC2 PRELIM 2020 9729/01/H2 11 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 = T oC You are also given that: relative molecular mass of ethanol = 46.0 enthalpy change of combustion of ethanol = –1370 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  c  T  46.0 m  1370  1000  100% B m  c  T  46.0 300  1370  1000  100% C 300  c  T  46.0 m  1370  100% D m  1370  1000 300  c  T  46.0  100% 12 When the temperature of a 2.0 dm 3 sample of a gas was changed from 20 C to k C at constant volume, the pressure of the gas was found to have increased from 1 atm to 2 atm. What is the value of k? A 10 B 40 C 313 D 586 thermometer can containing 300 g of water burner containing ethanol

7 ASRJC JC2 PRELIM 2020 9729/01/H2 [Turn over 13 The value of pV/RT is plotted against p for one mole of each of the three non –ideal gases D, E and F, where p is the pressure, V is the volume and T is the temperature of the gas. Which of the following gases could be D, E and F? D E F A NH3 H2O BF3 B H2O NH3 BF3 C BF3 NH3 H2O D H2O BF3 NH3 14 The following process is used to convert methane to hydrogen. CH4(g) + H2O(g) CO(g) + 3H2(g) H > 0 What will increase the yield of the reaction? 1 Adding argon gas to the mixture but keeping the total pressure constant.