MI H2 CHEM P1 Prelim

Class Adm No Candidate Name: This question paper consists of 14 printed pages. [Turn over 2011 Preliminary Examination II Pre-university 3 H2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 22 September 2011 Candidates answer on separate paper. 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use paper clips, highlighters, glue or correction fluid. Write your name and class on all the Answer Sweet in the spaces provided. There are forty 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.

2 SECTION A (30 MARKS) Answer all questions on the OMR form provided 1. When a water molecule accepts a proton to form an hydronium ion, the magnitude of the change in bond angle is A 2.5o B 15.5o C 60.0o D 5.0o 2. The number of atoms of gas in flask X is approximately A one-fifth the number of atoms of gas in flask Y. B equal the number of atoms of gas in flask Y. C half the number of atoms of gas in flask Y. D five times the number of atoms of gas in flask Y. 3. The use of the Data Booklet may be necessary for this question. Successive ionization energy (I.E.) of element Z was tabulated: No. of e- removed 1 2 3 4 5 6 7 8 9 I.E. / kJ mol-1 1351 2350 3565 5070 6240 7570 10710 12138 22274 The likely identity of Z is A Chlorine B Bromine C Argon D Krypton 10 g helium 10 g neon

[Turn over 3 4. Samples of 100 cm3 of the first four members of the alkene homologous series are burnt in 800 cm3 of oxygen. The total volume, V, of residual gas is measure at room temperature and pressure. Which one of the following graphs represents the results that will be obtained? A B C D 5. Which of the following chlorides is likely to have the least ionic character? A CsCl B LiCl C BeCl 2 D CaCl2 V / cm3 No. of carbon atoms 2 3 4 5 V / cm3 No. of carbon atoms 2 3 4 5 V / cm3 No. of carbon atoms 2 3 4 5 V / cm3 No. of carbon atoms 2 3 4 5

4 6. The variation in oxidation states across Period 3 oxides is shown in the graph below. The trend above is best explained by A the variation in first ionisation energy of Period 3 elements across the Period. B increase in electronegativity of the elements across Period 3. C the presence of partially filled 3p subshell. D the stability of the oxides increases across the Period. 7. 0.831 g of gas was released into a 8.31 dm 3 vessel at standard temperature. The pressure of the gas was found to be 5.2 kPa. What is the relative molecular mass of the gas? A 22.4 0.831 8.31  B 0.831 273 5.2 8.31   C 0.831 273 5.2  D 0.831 298 5.2  8. The rate equation for a reaction S2O8 2- (aq) + 2I- (aq)  2SO4 2- (aq) + I2 (aq) is given as rate = k [S2O8 2-] [I- ] where k is the rate constant. The reaction with initial concentrations of S2O8 2- at 1 x 10-4 mol dm-3 and I- at 9 x 10-1 mol dm-3 was investigated. A graph of S2O8 2- against time was plotted and the half life was determined to be 40 s. Determine the value of the rate constant, k. A 0.0173 B 0.0193 C 173 D 278 Maximum oxidation state of element Na Mg Al Si P S Cl

[Turn over 5 9. Zinc solid was added to aqueous hydrochloric acid in a conical flask. A suitable method to investigate the kinetics of a reaction between zinc and hydrochloric acid is to measure A the mass of the conical flask with its contents against time. B the colour intensity of the mixture against time. C the temperature of the mixture against volume of hydrochloric acid added. D the mass of precipitate formed against time. 10. The lattice energies of KI, RbCl and NaCl are -613 kJ mol-1, -659 kJ mol-1 and -756 kJ mol-1 respectively. What is the lattice energy of KBr likely to be? A -608 kJ mol-1 B -652 kJ mol-1 C -688 kJ mol-1 D -788 kJ mol-1 11. The above diagram is a reaction profile of a two-step reaction. What is the activation energy of the slow step? A +25 kJ mol-1 B +50 kJ mol-1 C +60 kJ mol-1 D +100 kJ mol-1 12. Which of the following resultant solutions will have the lowest pH? A 15 cm3 of 0.100 mol dm-3 KOH added to 15 cm3 of 0.050 mol dm-3 benzoic acid B 50 cm3 of 0.050 mol dm-3 KOH added to 25 cm3 of 0.100 mol dm-3 benzoic acid C 25 cm3 of 0.100 mol dm-3 KOH added to 50 cm3 of 0.100 mol dm-3 benzoic acid D 5 cm3 of 0.100 mol dm-3 KOH added to 50 cm3 of 0.100 mol dm-3 benzoic acid Energy / kJmol -1 Progress of reaction Reactants Products 0 10 25 -40 60

6 13. In the dissociation of NH4 + to NH3 and H+, So  -2.0 J K-1 mol-1. In contrast, in the dissociation of ethanoic acid in water, So  -91.6 J K-1 mol-1. The difference in entropy change of the two reactions is due to A an increased amount of water that is immobilised in the hydration spheres of H+ and ethanoate ions formed in the dissociation of ethanoic acid. B a faster rate of reaction between ethanoic acid and water. C an increased mixing of particles in water during the dissociation of ethanoic acid and water. D heat loss to surroundings during the dissociation of ethanoic acid and water. 14. Chromium picolinate [Cr(pic)3] is a common dietary supplement taken by athletes. The structure of the picolinate ion, pic, is The oxidation state of chromium in the complex is likely to be A -3 B 0 C +3 D +6 15. The use of the Data Booklet is relevant to this question. A current is passed through a simple cell as shown below: What could be an expected observation? A Sodium metal is deposited on the filter paper. B The size of the zinc foil reduced with time. C The filter paper turned blue. D A brown gas is observed. Filter paper moistened with NaNO3 (aq) zinc foil copper foil Connecting clips

[Turn over 7 16. The use of the Data Booklet is relevant to this question. The salt K 3Fe(CN)6 is prepared by oxidising K4Fe(CN)6. Which reagent can be used to carry out this oxidation? A H2O2 (aq) B Ag (s) C FeSO4 (aq) D CuF2 (aq) 17. The mechanism of propanone with iodine in the presence of an acid is shown below: Which statement is false? A Iodine is not involved in the rate-determining step. B The acid acts as a catalyst. C The rate of reaction is affected by temperature. D The overall order of reaction is one. 18. Consider these Period 3 oxides Na2O, SiO2 and P4O10. Which factor decreases from Na2O to SiO2 and also from SiO2 to P4O10? A Solubility in aqueous alkali B melting point C pH when mixed with water D Covalent character

8 19. Below is a scheme of reaction for a salt, Z. What is Z? A copper(II) sulfate B copper(II) bromide C chromium(III) bromide D chromium(III) sulfate 20. When propene is heated with aqueous HBr, which of the following compound is a possible product? A CCC H H H H OHH H H B CCC H OH H H Br H H H C CCC H Br H H Br H H H D CCC H OH H H OHH H H 21. The total possible number of structural isomers and stereoisomers of C3H5Br that are non- cyclic is A 2 B 3 C 4 D 5 an excess of BaCl2 (aq) white ppt in a brown solution white ppt in a green solution deep blue solution green solution add HCl (aq) an