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RAFFLES INSTITUTION 2015 YEAR 6 PRELIMINARY EXAMINATION Higher 1 CHEMISTRY 8872/01 Paper 1 Multiple Choice 28 September 2015 50 minutes Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not open this question booklet until you are told to do so. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and index number in the spaces provided on the Answer Sheet. 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 to be correct and record your choice with a soft pencil on the separate Answer Sheet. 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. This document consists of 12 printed pages. © Raffles Institution 2015 8872/01/S/15 [Turn over

2 © Raffles Institution 2015 8872/01/S/15 Section A There are thirty questions in this section. For each question, there are four possible answers, A, B, C, and D. Choose the one you consider to be correct and record your choice in soft pencil on the OMR sheet provided. 1 Azomethane, CH 3N2CH3, is a pale yellow liquid with a low boiling point. At elevated temperatures, azomethane decomposes into nitrogen and ethane gas. If 20 cm 3 of gaseous CH 3N2CH3 is completely decomposed, what is the total volume of gaseous products formed? [All volumes are measured at the same temperature and pressure.] A 50 cm3 B 40 cm3 C 25 cm3 D 10 cm3 2 Use of the Data Booklet is relevant to this question. Dickite, a clay-like material used as a coating for high-quality bond paper, has the following composition. SiO2: 46.54% Al2O3: 39.50% H2O: 13.96% The empirical formula of Dickite is SiwAlxHyOz. What is the value of z? A 13 B 9 C 4 D 2 3 Use of the Data Booklet is relevant to this question. A sample of 3-chloroprop-1-ene was heated with a halogen-containing reagent and compound X was formed. The relative molecular mass of X was determined to be 157.4. What was the reagent used? A HBr(g) B HCl(g) C Br2(g) D Cl2(g) 4 Which of the following elements would be expected to form the largest ion with a noble gas electron configuration? A Aluminium B Calcium C Chlorine D Sulfur

3 © Raffles Institution 2015 8872/01/S/15 5 Naturally occurring iron consists of various isotopes. Two ions formed by the isotopes are shown below: Fe2+ 26 54 Fe2+ 26 56 Which one of the following statements is correct? A Fe2+ 26 54 has a smaller ionic radius than Fe2+ 26 56 . B The electron configuration of both Fe2+ ions is 1s22s22p63s23p63d64s2. C When subjected to an electric field, Fe2+ 26 56 ion gives a greater angle of deflection than Fe2+ 26 54 ion. D The total number of protons and electrons in each of the Fe2+ ions is smaller than the nucleon number of the respective ion. 6 Sulfur forms a variety of oxides and oxo-anions. Which of the following series is arranged correctly in order of increasing bond angle? A SO2 < SO3 < SO4 2− < SO3 2− B SO3 2−< SO4 2−< SO3 < SO2 C SO3 2−< SO4 2−< SO2 < SO3 D SO2 < SO3 < SO3 2− < SO4 2− 7 Phosphorus can form PCl3 and PCl5. However, nitrogen can only form NCl3. Which statement is a correct explanation of this? A Nitrogen can attain an oxidation state of +5. B The N–Cl bond is weaker than the P–Cl bond. C The valence orbitals of P are higher in energy than that of N. D The n = 2 principal quantum shell can contain a maximum of 8 electrons. 8 In which of the following pairs can a hydrogen bond be formed between molecule I and molecule II? I II A water chlorine B oxygen hydrogen C ammonia ethanol D propanal ethanal [Turn over

4 © Raffles Institution 2015 8872/01/S/15 9 An energy profile diagram for a chemical reaction is given below. Which energy change is the activation energy for an uncatalysed reaction? 10 Which equation has a positive enthalpy change? A C2H5OH(l) + 3O2(g)  2CO2(g) + 3H2O(l) B Li(g)  Li+(g) + e C 2Cl(g)  Cl2(g) D I2(g)  I2(s) 11 The Maxwell-Boltzmann distribution for a gas at constant temperature is shown below. If the temperature of the gas is reduced by 10 oC, the graph changes shape. What happens to the values of n for the molecular energies X, Y and Z? X Y Z A higher higher higher B higher lower lower C lower lower higher D lower lower lower Energy Progress of reaction A B C D

5 © Raffles Institution 2015 8872/01/S/15 12 Water acts as an acid when it reacts with which of the following? I CN– II NH3 III HClO4 IV CH3COO– A I and IV only B II and III only C I, II and IV only D II, III and IV only 13 In the reaction shown below, the product, Mn 2+, also functions as a catalyst for the reaction. 2MnO4 – + 5H2C2O4 + 6H3O+  2Mn2+ + 10CO2 + 14H2O Which graph correctly describes the kinetics of the reaction? 14 The proton number of the element M is less than 20. The aqueous chloride of M is acidic, and gives a white precipitate when neutralised with NaOH(aq). This precipitate dissolves on reacting either with NaOH(aq) or with H2SO4(aq). In which Group of the Periodic Table is M likely to be found? A II B III C IV D V [Turn over

6 © Raffles Institution 2015 8872/01/S/15 15 Which property when plotted against increasing atomic number gives the shape of the following graph? A Melting point of NaCl, MgCl2, AlCl3 and SiCl4 B First ionisation energy of Mg, Ca, Sr and Ba C Electrical conductivity of Na, Mg, Al and Si D Electronegativity of Si, P, S and Cl 16 Which statement is correct about the chemical properties of the oxides of the elements in Period 3? A Al2O3 is soluble in both KOH and HCl. B P2O5 reacts with water to give OH− ions. C SiO2 forms a solution of pH 6 when added to water at room temperature. D Na2O and MgO can be mixed in water to give an approximately neutral solution. 17 Damascenone is part of a class of compounds called rose ketones. When one molecule of damascenone reacts with bromine by electrophilic addition, how many bonds are broken and formed in damascenone? Number of σ bonds broken Number of 𝜋 bonds broken Number of new σ bonds formed A B C D 0 1 0 1 2 2 3 3 2 4 6 8 atomic number

7 © Raffles Institution 2015 8872/01/S/15 18 The following gaseous equilibrium was established in an experiment. H2(g) + I2(g) ⇌ 2HI(g) At a particular time, t, extra I2(g) was added. Which of the following sets of curves shows how this system responds to the addition? A C B D 19 What is the ratio of monochlorinated products when the molecule below r eacts with chlorine in UV light? A 3:1:1 B 2:1:2 C 3:1 D 2:1 t pressure time HI H2 I2 t pressure time HI I2 H2 t pressure time H2 I2 HI t pressure time H2 I2 HI [Turn over

8 © Raffles Institution 2015 8872/01/S/15 20 Which statement best explains why benzene does not undergo addition reactions? A It has three 𝜋 bonds. B It is resonance stabilised. C It is an unsaturated compound. D It is a liquid at room temperature. 21 An alcohol was treated with hot acidified potassium dichromate( VI). The separated organic product gave an orange precipitate with 2,4 -dinitrophenylhydrazine reagent, but no silver mirror with