ngee ann comb chem 2024 p4 QP + answer

Name: …………………………………………. Register no: …….…. Class: ……..…. NGEE ANN SECONDARY SCHOOL NA PRELIMINARY EXAMINATION SCIENCE 5105/04 2 August 2024 Paper 4 Chemistry Candidates answer on the Question Paper. Papers 3 and 4: 1 hour 15 minutes No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, register number and class on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. The use of an approved scientific calculator is expected, where appropriate. In calculations, you should show all the steps in your working, giving your answer at each stage. You are advised to spend no longer than 30 minutes on Paper 3. You may proceed to answer Paper 4 as soon as you have completed Paper 3. A copy of the Periodic Table is printed on page 2. At the end of the examination hand in your answers to Paper 3 and Paper 4 separately. The number of marks is given in brackets [ ] at the end of each question or part question. Check by student: _____________________ Date: _________ This document consists of 13 printed pages and 1 blank pages. For Examiner’s Use Section Marks Paper 3 /20 Paper 4 – Section A /22 Paper 4 – Section B /8 Total /50

2 NAS/2024/Preliminary Examination/4NA/SCIENCE(CHEMISTRY) 5105 The Periodic Table of Elements Group 1 2 13 14 15 16 17 18 Key 1 H hydrogen 1 2 He helium 4 3 Li lithium 7 4 Be beryllium 9 proton (atomic) number atomic symbol name relative atomic mass 5 B boron 11 6 C carbon 12 7 N nitrogen 14 8 O oxygen 16 9 F fluorine 19 10 Ne neon 20 11 Na sodium 23 12 Mg magnesium 24 3 4 5 6 7 8 9 10 11 12 13 Al aluminium 27 14 Si silicon 28 15 P phosphorus 31 16 S sulfur 32 17 Cl chlorine 35.5 18 Ar argon 40 19 K potassium 39 20 Ca calcium 40 21 Sc scandium 45 22 Ti titanium 48 23 V vanadium 51 24 Cr chromium 52 25 Mn manganese 55 26 Fe iron 56 27 Co cobalt 59 28 Ni nickel 59 29 Cu copper 64 30 Zn zinc 65 31 Ga gallium 70 32 Ge germanium 73 33 As arsenic 75 34 Se selenium 79 35 Br bromine 80 36 Kr krypton 84 37 Rb rubidium 85 38 Sr strontium 88 39 Y yttrium 89 40 Zr zirconium 91 41 Nb niobium 93 42 Mo molybdenum 96 43 Tc technetium – 44 Ru ruthenium 101 45 Rh rhodium 103 46 Pd palladium 106 47 Ag silver 108 48 Cd cadmium 112 49 In indium 115 50 Sn tin 119 51 Sb antimony 122 52 Te tellurium 128 53 I iodine 127 54 Xe xenon 131 55 Cs caesium 133 56 Ba barium 137 57–71 lanthanoids 72 Hf hafnium 178 73 Ta tantalum 181 74 W tungsten 184 75 Re rhenium 186 76 Os osmium 190 77 Ir iridium 192 78 Pt platinum 195 79 Au gold 197 80 Hg mercury 201 81 Tl thallium 204 82 Pb lead 207 83 Bi bismuth 209 84 Po polonium – 85 At astatine – 86 Rn radon – 87 Fr francium – 88 Ra radium – 89–103 actinoids 104 Rf rutherfordium – 105 Db dubnium – 106 Sg seaborgium – 107 Bh bohrium – 108 Hs hassium – 109 Mt meitnerium – 110 Ds darmstadtium – 111 Rg roentgenium – 112 Cn copernicium – 113 Nh nihonium – 114 Fl flerovium – 115 Mc moscovium – 116 Lv livermorium – 117 Ts tennessine – 118 Og oganesson – lanthanoids 57 La lanthanum 139 58 Ce cerium 140 59 Pr praseodymium 141 60 Nd neodymium 144 61 Pm promethium – 62 Sm samarium 150 63 Eu europium 152 64 Gd gadolinium 157 65 Tb terbium 159 66 Dy dysprosium 163 67 Ho holmium 165 68 Er erbium 167 69 Tm thulium 169 70 Yb ytterbium 173 71 Lu lutetium 175 actinoids 89 Ac actinium – 90 Th thorium 232 91 Pa protactinium 231 92 U uranium 238 93 Np neptunium – 94 Pu plutonium – 95 Am americium – 96 Cm curium – 97 Bk berkelium – 98 Cf californium – 99 Es einsteinium – 100 Fm fermium – 101 Md mendelevium – 102 No nobelium – 103 Lr lawrencium –

3 NAS/2024/Preliminary Examination/4NA/SCIENCE(CHEMISTRY) 5105 Section A Answer all questions. 1. Choose from the substances listed to answer the questions. NH4Cl Na2CO3 Al2O3 CH3Cl K3PO4 Each substance may be used once, more than once or not at all. Identify the substance which (a) reacts with both acid and alkali to form salt and water. ……………………………………………………………………………………….……. [1] (b) contains a total of eight atoms. …………………………………………………………………………………………..… [1] (c) reacts with aqueous sodium hydroxide to produce a gas which turns moist red litmus paper blue. .…………………………………………………………………………………………..… [1] [Total: 3 marks]

4 NAS/2024/Preliminary Examination/4NA/SCIENCE(CHEMISTRY) 5105 2. A student measures accurately a fixed volume of 25.0 cm 3 of a known concentration of dilute hydrochloric acid into a glass beaker. She measures the initial temperature of the hydrochloric acid. She then adds 30.0 cm 3 of excess potassium hydroxide into the acid and stirs. The final temperature of the mixture is recorded. (a) State the type of apparatus or instrument that the student used to measure th e following quantities: 25.0 cm3 of dilute hydrochloric acid ……………………………………………….. 30.0 cm3 of potassium hydroxide ………………………………………………. temperature of the solutions ……………………………………………….. [2] (b) Figure 2.1 shows initial and final temperatures recorded. Fig. 2.1 Use the information provided in Fig. 2.1 to complete Table 2.1. Indicate whether the temperature change is a positive (+) or negative (–) value. The initial temperature has been recorded in the table. [2] initial temperature / oC 19.0 final temperature / oC temperature change / oC (final temperature – initial temperature) Table 2.1 (c) Write an ionic equation, including state symbols, for the reaction of dilute hydrochloric acid and aqueous potassium hydroxide. …………………………………………………………………………………………… [1] [Total: 5 marks]

5 NAS/2024/Preliminary Examination/4NA/SCIENCE(CHEMISTRY) 5105 3. Table 3.1 shows the boiling points in Kelvin of five alkenes, A, B, C, D and E. Hydrocarbon A B C D E Number of carbon atoms per molecule 2 3 4 5 6 Boiling point / K 160 267 303 337 Table 3.1 (a) Plot a graph of boiling point against number of carbon atoms for these alkenes, marking each point with a cross (x). Draw a best-fit line for the points plotted. [2] (b) From the graph, find the boiling point of alkene B. ………………………………………………………………………………….……..…… [1] (c) (i) Alkene A was reacted with aqueous bromine. State an observation made during this reaction. ……………………………………………………………………………….……..…. [1] Number of carbon stoms 350 300 250 200 150 Boiling point / K

6 NAS/2024/Preliminary Examination/4NA/SCIENCE(CHEMISTRY) 5105 (ii) Draw the full structural formula of the product obtained when alkene A reacts with b