VS 2022 O Level Pure Chemistry P1+P2 Answer Scheme

2022 Answer1 Victoria School2022 Chemistry O Levels / 6092Suggested Answer Key PAPER 1Q1Q2Q3Q4Q5Q6Q7Q8Q9Q10Q11Q12Q13Q14Q15Q16Q17Q18Q19Q20AACBBDDDCCCBDDADABCCQ21Q22Q23Q24Q25Q26Q27Q28Q29Q30Q31Q32Q33Q34Q35Q36Q37Q38Q39Q40ADBAADDDABCCCDBBBBAAPAPER 2 (SECTION A)QuestionAnswerMarkA1aM 1bR 1cMQ3 1dT 1eQ and Z1fRQ4 1A2aThe perfume molecules/particles are always in random motion and will diffuse from a region of higher concentration to a region of lower concentration.1bThe particles must be packed closely together and in disorderly arrangement.The label “a few seconds later” should be changed to a few minutes/hours later.11cThe distance moved by the ions in beaker B will be larger than that in beaker A.Since the water in beaker B is at a higher temperature of 30 C, the ions will gain more heat from it and hence possess higher kinetic energy resulting in higher rate of diffusion.11

2022 Answer2 The distance moved by V2+ ions in beaker C will be larger than Cu2+ ions in beaker A.V has an Ar of 51 while Cu has an Ar of 64. V2+ ions will diffuse faster due to their lower mass and cover a larger distance in the same amount of time.11A3acarboxylic acidalkenealcohol1biAdd aqueous brominechanges reddish-brown bromine to colourless11biiB is a weak acid which dissociate partially when dissolved in water to produce a low concentration of H+ ions.1biiiD will be oxidisedto form ethanoic acid.11cielementCHOmass per 100 g / g40.06.753.3amount / molmole ratio3.33 ÷ 3.33 = 16.7 ÷ 3.33 = 23.33 ÷ 3.33 = 1empirical formulaCH2O 111ciiCompound BCompound B has molecular formula C2H4O2/the ratio of C:H:O is 1:2:1.1A4ahalogencolour and state at room temperature and pressurechlorineyellow green colour and gaseous statebrominereddish brown colour and liquid stateiodinepurple black colour and solid state colour [1]state [1]biThe reactivity of the halogens decreases down the Group. (must state but no mark)Chlorine, being placed on top of bromine and iodine, is the most reactive as it can displace both bromine and iodine from their respective halide solutions.Bromine, being placed below chlorine but above iodine, is less reactive than chlorine and hence unable to displace chlorine from the chloride solution, but more reactive than iodine and hence can displace iodine from the iodide 11

2022 Answer3 solution.Iodine, being placed below chlorine and bromine, is the most unreactive as it neither displace chlorine nor bromine from their respective halide solutions.biiIn A, aqueous bromine has displace iodine from aqueous iodide forming the brown aqueous iodine.In B, aqueous iodine is present and did not undergo any reaction.1cThe fluorine molecule gains two electrons readily during chemical reactions and is reduced to two fluoride ions.1diAlthough the Cl atom reacted with the O3 molecule to form ClO, the ClO reacts with another ozone molecule to form back Cl atom. Hence, the Cl atom remains chemically unchanged at the end of the reaction.1diiCl atoms will react and break down O3 molecule