2021 PU1 H2 EOY P1

Class Adm No Candidate Name: This question paper consists of 18 printed pages and 2 blank pages. 2021 End-of-Year Examination Pre-University 1 H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice & Structured Questions 15 Oct 2021 2 hours Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so Write your name, class and admission number on all the work you hand in. For Section A, there are fifteen questions. 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 Multiple Choice Answer Sheet provided. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Read the instructions on the Multiple Choice Answer Sheet very carefully. For Section B, 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. Answer all the questions. The use of an approved scientific calculator is expected , where appropriate. Any rough working should be done in this question paper. Question Section A 1 2 3 4 5 6 7 Total Marks 15 6 9 16 6 6 3 9 70

2 Section A – Multiple Choice For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which statements about cyclohexane are correct? C C C C C C H H H H H H H H H HH H cyclohexane 1 Its empirical formula is CH2. 2 Its molecular formula is C6H12. 3 Its relative molecular mass is 48.0. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 2 Some hydrocarbon gas was combusted in excess oxygen at room temperature and pressure. volume of hydrocarbon gas combusted 10 cm3 volume of oxygen available before combustion 90 cm3 total volume of gases after combustion 70 cm3 remaining volume of gas after passing gases through NaOH(aq) 40 cm3 What is the molecular formula of the hydrocarbon? A C3H6 B C3H8 C C4H8 D C4H10 3 Which statement about beryllium chloride, BeCl2, is correct? A BeCl2 has a bent shape. B BeCl2 is an ionic compound. C BeCl2 can behave as a Lewis acid. D BeCl2 accepts electrons into the 1s orbital of the Be atom.

3 [Turn over 4 When zinc nitrate is heated strongly, it decomposes to form zinc oxide and two gases. 2Zn(NO3)2(s) ⟶ 2ZnO(s) + 4NO2(g) + O2(g) Which statement about the decomposition of zinc nitrate is correct? A Zinc nitrate was neither oxidised nor reduced. B Zinc nitrate was oxidised to form zinc oxide. C Zinc nitrate was oxidised to form nitrogen dioxide. D Zinc nitrate was oxidised to form oxygen. 5 In an experiment, UV rays were shone on some chlorine atoms. The chlorine atoms that absorbed a UV ray were found to have the electronic configuration 1s2 2s2 2p6 3s1 3p6. What was the change in the chlorine atom due to the absorption of the UV ray? A An electron was demoted from the 4s to 3p subshell. B An electron was gained by the atom to the 3p subshell. C An electron was lost by the atom from the 3s subshell. D An electron was promoted from the 3s to 3p subshell. 6 Which atom has the highest number of half-filled orbitals? A C B F C Mg D Al 7 How many sigma (σ) and pi (π) bonds are present in one molecule of acrylonitrile? C C C N H H H acrylonitrile σ bonds π bonds A 4 3 B 4 5 C 6 3 D 6 5

4 8 Which ionic compound has the highest melting point? A CaF2 B CaO C K2O D KF 9 Hexagonal boron nitride consists of boron and nitrogen atoms forming covalent bonds with one another in an extensive hexagonal network. All boron and nitrogen atoms in the network use up all of their available valence electrons to form covalent bonds. Which statement is a correct property of hexagonal boron nitride? A It is a good conductor of electricity. B It is ductile and malleable. C It is hard. D It has a high melting point. 10 Which substance is ductile and malleable? melting point / °C electrical conductivity in different states (s) (l) (aq) A 122    B 181   insoluble C 373   insoluble D 802    boron atom nitrogen atom

5 [Turn over 11 Which statement correctly describes an ideal gas assumption? A Molecules occupy an insignificant volume in the container. B A gas is most ideal under high pressure and low temperature conditions. C Kinetic energy is completely converted to heat energy after molecules collide. D Only instantaneous dipole-induced dipole forces of attraction exist between molecules. 12 A gas canister holds 3.00 dm3 of propane at 300 kPa and 0 °C. What is the volume of the propane when it is released at standard temperature and pressure? A 1.01 dm3 B 8.88 dm3 C 9.00 dm3 D 9.82 dm3 13 Which graph correctly shows the relationship between variables for a sample of a fixed mass of an ideal gas? A B C D p T constant V pV 1 T 1 p V V T constant T constant p

6 14 Experiments were performed on four gases that can be found in the atmosphere – N2, O2, Ar, and CH4. The volumes and pressures of equal masses of each gas were measured over a range of temperatures. The results are plotted on a graph of pV against T (in units of K). All the gases are assumed to be behaving ideally. Which graph shows the results for O2? 15 How many enantiomers (optical isomers) of D-glucose are present? H O OH OH OH OH OH D-glucose A 4 B 8 C 16 D 32 END OF SECTION A pV T A B C D

7 [Turn over Section B – Structured Questions Answer all questions. 1 Two redox reactions were used to determine the unknown concentration of a solution. In the first reaction, acidified potassium manganate(VII) reacts with potassium iodide to liberate iodine. (a) Write two balanced ion-electron equations for the first reaction. ............................................................................................................................................... .......................................................................................................................................... [2] In the second reaction, the iodine that was liberated reacts with sodium thiosulfate (Na2S2O3), forming sodium tetrathionate (Na2S4O6). (b) Write the overall ionic equation for the second reaction. .......................................................................................................................................... [1] 10.0 cm3 of aqueous acidified potassium manganate(VII) was pipetted into a conical flask. Excess aqueous potassium iodide was then added into the conical flask and the solution turned orange. The orange mixture was titrated with 1.50 mol dm–3 aqueous sodium thiosulfate. 24.90 cm3 of aqueous sodium thiosulfate was required to reach end-point. (c) Calculate the number of moles of iodine liberated from the first reaction. [1] (d) Calculate the number of moles of manganate(VII) ions reacted. [1] (e) Calculate the concentration (in mol dm–3) of aqueous potassium manganate(VII) used. [1] [Total: 6]

8 2 Nitrogen is the most abundant gas in the atmosphere. In the upper atmosphere, a high intensity of cosmic rays can be found. These cosmic rays constantly split apart some nitrogen molecules, formin