ACJC H2 Chem 2012 Prelim P1 QP

© ACJC 2012 9647/01/Prelim/12 [Turn over 1 ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination CHEMISTRY 9647/01 Higher 2 Paper 1 Multiple Choice 12 September 2012 1 hour Additional Materials: Multiple Choice Answer Sh eet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, Centre number and candidate number on the answer sheet in the spaces provided unless this has been done for you. There are forty questions in 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. This document consists of 18 printed pages. 9647/01/Prelim/012 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2012 Department of Chemistry [Turn over

© ACJC 2012 9647/01/Prelim/12 [Turn over 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 The relative atomic mass of antimony, which consist s of the isotopes 121 Sb and 123 Sb, is 121.8. What is the percentage of 123 Sb in the isotopic mixture? A 40% B 45% C 50% D 55% 2 20 cm 3 of a gaseous unknown hydrocarbon was combusted in 100 cm 3 (an excess) of oxygen. After the combustion, the mixtur e was left to cool and the gaseous volume was 90 cm 3. Upon treatment with potassium hydroxide, the volume was decreased to 50 cm 3. What is the molecular formula of the unknown hydrocarbon? A CH 4 B C2H2 C C2H6 D C3H6 3 Species with unpaired electrons exhibit a property known as paramagnetism, that is, it is attracted by an external magnetic fi eld which is directly proportional to the number of unpaired electrons present in the species. Which of the following species is not paramagnetic? A Fe 3+ B Ti 2+ C Cu 2+ D Ca 2+

© ACJC 2012 9647/01/Prelim/12 [Turn over 3 4 The empirical formula of a fluorocarbon is CF 2. At the same temperature and pressure, 1 dm 3 of the fluorocarbon weighs 8.93 g while 1 dm 3 of fluorine gas weighs 1.80 g. What is the molecular formula of the fluorocarbon? A CF 2 B C2F4 C C4F8 D C5F10 5 Which of the following molecules will not form a hydrogen bond with another of its own molecules? A CH 3NH 2 B CH 3COCH 3 C CH 3CONH 2 D CH 3OH 6 Adrenaline is a hormone which, when secreted direct ly into the bloodstream, acts as a stimulant. The structure of adrenaline is given below. What are the values of the angles x, y and z in a molecule of adrenaline? x y z A 120º 105º 107º B 109º 180º 90º C 120º 105º 120º D 180º 120º 107º HO C HO O H C H H N H CH3 H x y z

© ACJC 2012 9647/01/Prelim/12 [Turn over 4 7 Propene burns completely in oxygen to give carbon dioxide and water. CH 3CH=CH 2 + 9/2 O 2 3 CO 2 + 3 H 2O Using the Data Booklet, calculate the enthalpy change of the reaction. A - 890 kJ mol -1 B - 1548 kJ mol -1 C - 2569 kJ mol -1 D - 2890 kJ mol -1 8 Which graph correctly represents an auto-catalytic reaction (reaction in which one of the products catalyses the reaction)? A C B D Rate Time Rate Time Rate Time Rate Time

© ACJC 2012 9647/01/Prelim/12 [Turn over 5 9 0.12 g of graphite was added to a vessel that conta ined CO 2 (g) at a pressure of 0.824 atm at 400K. The total pressure reached an equilibrium value of 1.366 atm after a period of time. C(graphite) + CO 2 (g) 2 CO (g) Given that the temperature did not change, what is the value of the equilibrium constant K p? A 0.239 B 0.260 C 3.84 D 4.17 10 What is the pH of the final solution formed when V cm 3 of dilute sulfuric acid of pH 2.0 is mixed with V cm 3 of dilute sulfuric acid of pH 4.0 followed by the addition of 2V cm 3 of water? A 2.3 B 2.6 C 3.0 D 3.6

© ACJC 2012 9647/01/Prelim/12 [Turn over 6 11 When 5.00 cm 3 of a 0.100 mol dm −3 base is titrated against 0.100 mol dm − 3 of ethanoic acid, CH 3COOH, the following titration curve is obtained. Which of the following correctly identifies the bas e used and the point on the curve at which pH = p K a? Base used Point where pH = p Ka A NaOH(aq) M B Ba(OH) 2(aq) N C NaOH(aq) P D Ba(OH) 2(aq) P 12 A sparingly soluble salt, cobalt(II) hydroxide, dis sociates in aqueous solution according to the equation below. Co(OH) 2 (s) Co 2+ (aq) + 2 OH - (aq) What is the concentration of OH - at equilibrium given that the solubility product of cobalt(II) hydroxide is 1.6 x 10 -15 mol 3 dm -9? A 7.37 x 10 -6 mol dm -3 B 9.28 x 10 -6 mol dm -3 C 1.47 x 10 -5 mol dm -3 D 2.34 x 10 -5 mol dm -3 Volume of 0.100 mol dm −3 Of CH 3COOH / cm 3 pH 14 12 10 8 6 4 2 0 0 2 4 6 8 10 12 14 16 18 20 P M N

© ACJC 2012 9647/01/Prelim/12 [Turn over 7 13 The following reaction has a negative E θ cell so it does not occur under standard conditions. 2NO 3 -(aq) + 8H +(aq) + 6C l-(aq) 2NO (g) + 4H 2O ( l) + 3C l2(g) However, the reaction may be made to proceed under non-standard conditions. Which of the following changes will not aid the reaction to proceed? A Addition of NaC l B Addition of HC l C Addition of KNO 3 D Addition of AgC l 14 Use of the Data Booklet is relevant to this question. Sacrificial protection is a common method used to p revent the rusting of large steel objects such as underground pipes, oil tankers or ships. A piece of metal that is more reactive than iron is connected to the object made of iron. Over time, the more reactive metal will co rrode in place of the iron and hence “sacrificed”. Which metal can be used in the above mentioned method to prevent rusting? A Copper B Zinc C Cobalt D Lead 15 Which of the following species has the smallest radius? A S2- B Cl- C K+ D Ca 2+

© ACJC 2012 9647/01/Prelim/12 [Turn over 8 16 A mixture of the oxides of two elements in the third period is dissolved in water. The resultant solution is acidic. What could be the constituents of the mixture? A Na 2O and MgO B Na 2O and Al2O3 C Al2O3 and SiO 2 D SO 3 and P 4O10 17 X, Y and Z are Group II elements. They form compounds with th e following properties: • Y(NO 3)2 has a higher thermal decomposition temperature than Z(NO 3)2. • XSO 4 has a more exothermic lattice energy than ZSO 4. Which of the following statements is correct? A On heating, Y(NO 3)2 decomposes to the nitrite and oxygen while Z(NO 3)2 decomposes to the oxide, nitrogen dioxide and oxygen. B XCl2 has a more covalent character than YCl2. C Z is more reducing than Y. D X is Mg and Z is Ba. 18 0.03 mol of chlorine gas was bubbled into 100 cm 3 of hot aqueous sodium hydroxide of concentration, 1.5 mol dm -3. Which of the following statement is correct regarding the above reaction? A 0.03 mol of sodium chlorate (I) was formed. B 0.03 mol of sodium chlorate (V) was formed. C The excess sodium hydroxide required 0.06 mol of dilute hydrochloric acid for complete neutralization. D The chloride produced required 0.05 mol of silver nitrate for complete