MI H2 CHEM P1 Prelim

Class Adm No Candidate Name: This document consists of 17 printed pages and 1 blank page. [Turn over 2014 Preliminary Examination II Pre-university 3 H2 CHEMISTRY 9647/01 Paper 1 Multiple Choice Thursday, 25 September 2014 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. 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. The use of an approved scientific calculator is expected, where appropriate.

2 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 Use of the Data Booklet is relevant to this question. The compound KAl(SO4)2 is used in the purification of water. Which one of the following statements about 155 g of this compound is correct? A It contains 0.6 moles of cations. B It contains 7.22 x 1023 anions. C There are a total of 2.17 x 1024 ions. D There are more anions than cations. 2 15 cm 3 of a gaseous hydrocarbon was completely burnt in 50 cm3 of oxygen. The products were cooled to room temperature and then passed through aqueous NaOH. The total volume of gas decreased to 5 cm3. What is the molecular formula of the hydrocarbon? All gas volumes were measured at the same temperature and pressure. A CH4 B C2H2 C C2H4 D C2H6 3 Use of the Data Booklet is relevant to this question. Which of the following particles, on losing an electron, has a half-filled set of orbital? A Co3+ B Mn2+ C P2– D Se+ 4 Which of the following statements can be explained in terms of the existence of intermolecular hydrogen bonding? A Boiling point of pentane is higher than that of 2,2-dimethylpropane. B Hydrazine (N2H4) can act as a base. C Propan-2-ol has a higher boiling point than propanone. D Sodium hydride has a high melting point.

[Turn over 3 5 In which of the following are both chemical species non-planar? A BeCl4 2-, ●CH3 B COCl2, PCl4 + C SeO3, CCl3 – D XeF6, C2Cl4 6 For a fixed mass of an ideal gas, which of the following graphs , when plotted, does not show a curve? (ρ = density of the gas) A V against (at constant P) B P against ρT C against V D T against 7 Which of the following statements helps to explain why calcium and oxygen form CaO instead of Ca2O? A Less energy is required to form Ca+ than Ca2+ from a calcium atom. B Lattice energy of Ca2O is less exothermic than that of CaO. C More energy is released in forming the oxide ions from oxygen molecules in the formation of CaO than from the formation of Ca2O. D When Ca2O is formed from its elements, more energy is released than when CaO is formed. 8 Use of the Data Booklet is relevant to this question. Ethyne, C2H2, reacts with hydrogen iodide to form 1,2-diiodoethane. What is the standard enthalpy change for the reaction? A +138 kJ mol-1 B -212 kJ mol-1 C -511 kJ mol-1 D -810 kJ mol-1

4 9 Use of the Data Booklet is relevant to this question. The standard reduction potential of a chlorate ion is 2ClO3 – + 12H+ + 10e– ⇌ Cl2 + 6H2O E = +1.47 V Which of the following statements regarding the mixing of aqueous Sn2+ and ClO3 – under acidic condition is correct? A No reaction occurs. B pH decreases as the reaction proceeds. C The oxidation number of chlorine is reduced by 5. D The oxidation number of tin is reduced by 2. 10 Use of the Data Booklet is relevant to this question. An aqueous chromium(III) solution was electrolysed using a large current. After 30 mins, p mol of chromium and q dm3 of hydrogen gas were formed at the cathode. How many moles of electrons were involved in the reaction? (All volumes were measured at s.t.p.) A 22.4 qp  B 22.43 qp  C 11.2 qp  D 11.23 qp  11 Nitrogen dioxide dimerises into dinitrogen tetroxide: 2NO2 ⇌ N2O4(g) H < 0 When the pressure of a sample of nitrogen dioxide in a container of fixed volume was investigated, the following graph was obtained. time PNO2 X Y Which of the following could best account for the changes at X and Y? X Y A NO2 was added. Temperature decreased. B NO2 was added. Temperature increased. C NO2 was removed. Temperature decreased. D NO2 was removed. Temperature increased.

[Turn over 5 12 On a cold planet where water exists as frozen solid and ammonia is running freely as liquid on its surface, which of the following statements regarding ammonia medium based chemistry is incorrect? A CH3NH2 acts as an acid. B KNH2 acts as a base. C NH4 + is the conjugate acid of ammonia. D The ionic equation for an acid-base reaction is NH4 + + NH2 –  2NH3 13 25.0 cm3 of 0.100 mol dm-3 of monobasic acid W is reacted with 0.0500 mol dm-3 of aqueous sodium hydroxide. Ka for acid W = 1.76 x 10-5 mol dm-3. What are the values of f, g and h? f g h A 12.5 3.12 8.73 B 12.5 4.75 8.73 C 25.0 3.03 8.64 D 25.0 4.75 8.64 pH Volume of NaOH(aq) added / cm3 7 13 f 2f g h

6 14 An exothermic reaction is known to proceed in two steps, with the second step being the rate determining step. Which of the following energy profile diagrams best describes the reaction? A Energy Progress of Reaction Reactants Products B Energy Progress of Reaction Reactants Products C Energy Progress of Reaction Reactants Products D Energy Progress of Reaction Reactants Products 15 For a reaction between molecules E and F: E + 2F  2G Experiment Initial concentration of E / mol dm-3 Initial concentration of F / mol dm-3 Initial rate / mol dm-3 s-1 1 1.5 2.0 1.25 x 10-4 2 3.0 4.0 5.0 x 10-4 3 6.0 4.0 1.0 x 10-3 Which of the following statements is incorrect? A Only 1 molecule of F is involved in the rate determining step. B The overall order of reaction is 2. C The reaction occurs in one step. D The unit for the rate constant is mol-1 dm3 s-1.

[Turn over 7 16 The following diagram shows the third ionisation energies of four consecutive Period 3 elements. Two other properties of the same elements are shown in the following diagrams. What are properties R and S? Property R Property S A electrical conductivity boiling point B electronegativity effective nuclear charge C melting point electronegativity D second ionisation energy ionic radius 17 Which of the following statements about Group II elements is correct? A The electronegativity increases down the group. B The ionic radius increases down the group. C The ionisation energy increases down the group. D The reducing power decreases down the group.   