AJC H1 CHEM P1

ANDERSON JUNIOR COLLEGE 2009 PRELIMINARY EXAMINATION HIGHER 1 _________________________________________________________________________________ CHEMISTRY 8872/01 Paper 1 Multiple Choice 18 September 2009 5 0 m i n u t e s 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 and PDG. Write your NRIC / FIN and shade the digits accordingly. 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 correct and record your choice in 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 paper consists of 10 printed pages including this cover page.

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 Copper, in the form of CuFeS 2, is extracted from ores in copper mines. The ore contains 1.0 % by mass of copper. What percentage of the ore contains CuFeS2, if it is the only copper-containing component of the ore? A 1.0 % B 2.9 % C 3.46 % D 34.6 % 2 When the salt (C2H5)4N+Cl– is treated with hydrogen chloride, a white ionic solid E is formed. When E is dissolved in water, a 20 cm 3 sample of the solution requires 24 cm 3 of 0.1 mol dm –3 NaOH for neutralization. Another 20 cm 3 sample of the solution requires 48 cm 3 of 0.1 mol dm –3 AgNO 3 for complete precipitation of chloride as AgCl. What could be the formula of the anion in E? A HCl 2 – B HCl3 2– C H2Cl3 – D H2Cl5 3– 3 Wines often contain a small amount of sulfur dioxide that is added as a preservative. The sulfur dioxide content of a wine can be found by titrating with aqueous iodine, I2, to give iodide, I-. The sulfur dioxide becomes oxidised in the process. SO2 + 2H2O  SO4 2- + 4H+ + 2e- In an experiment, a student found that the sulfur dioxide in a 100 cm 3 sample of white wine reacted with exactly 20.00 cm3 of 0.01 mol dm-3 aqueous iodine. What is the concentration of sulfur dioxide in the sample of white wine, in mol dm-3? A 1.00 x 10−4 B 2.00 x 10−4 C 1.00 x 10−3 D 2.00 x 10−3 4 Chlorine has the electronic configuration 1s2 2s2 2p6 3s2 3p5. Which chlorine compound is not likely to exist? A KClO5 B CuCl C Cl2O7 D Cl2O

3 5 Gallium nitride, GaN, could revolutionise the design of electric light bulbs because only a small length used as a filament gives excellent light at low cost. Gallium nitride is an ionic compound containing the Ga 3+ ion. What is the electronic configuration of the nitrogen ion in gallium nitride? A 1s2 2s2 B 1s2 2s2 2p3 C 1s2 2s2 2p4 D 1s2 2s2 2p6 6 Gaseous particle G has a proton number n and a charge of + 1. Gaseous particle H has a proton number of (n + 1) and is isoelectronic with G. G and H have the same number of neutrons. Which of the following statements incorrectly describes G and H? A The charge on G is half that on H. B G has a larger ionic radius than H. C G requires lesser energy than H when a further electron is removed from each particle. D G will be deflected by a larger magnitude than H when each particle is passed through an electric field. 7 In which of the following reactions is the bond angle in the product greater than that in the first reactant? A H2O + H+  H3O+ B CO2 + OH–  HCO3 – C C2H4 + H2  C2H6 D CH3CHO + HCN  CH3CH(OH)CN

4 8 When two liquids are mixed, heat may be evolved if intermolecular forces formed are stronger than those broken, even if there is no chemical reaction. Which pair of liquids, when mixed, will give out heat? A CH 3Cl and C6H14 B CH2Cl2 and (CH3)2CO C CCl4 and (CH3)2CO D CCl4 and CH3CH2OH 9 Which of the following statements cannot be explained by hydrogen bonding? A Ice floats on water. B Propanoic acid has a higher boiling point than methyl ethanoate. C The relative molecular mass of ethanoic acid is 120 in the gaseous state under high pressure. D Sodium hydrogen carbonate is soluble in water. 10 Given the following standard enthalpy changes, H  c (C) = - 394 kJ mol-1 H c (H2) = - 286 kJ mol-1 H f (C2H5OH) = - 278 kJ mol-1 What is the standard enthalpy change of combustion of ethanol, C 2H5OH? A - 402 kJ mol-1 B - 758 kJ mol-1 C - 1368 kJ mol-1 D - 1924 kJ mol-1

5 11 The use of the Data Booklet is relevant to this question. Ethanol is prepared industrially by the reaction of ethene and steam in the presence of a catalyst. C 2H4 (g) + H2O (g) C2H5OH (g) What is the enthalpy change for the reaction? A - 50 kJ mol -1 B + 50 kJ mol-1 C - 310 kJ mol-1 D + 310 kJ mol-1 12 In the presence of dilute sulfuric acid, sodium chromate(VI), Na2CrO4, reacts as follows: 2CrO4 2- (aq) + 2H+ (aq) Cr2O7 2- (aq) + H2O (l) yellow orange Which one of the following statements is correct? A When a few drops of sodium hydroxide is added to a solution of sodium dichromate, Na 2Cr2O7, the solution turns yellow. B In the forward reaction, chromium has undergone oxidation. C When the pressure is increased, the yellow solution of sodium chromate( VI), Na 2CrO4, turns orange . D The equilibrium constant, Kc, of this reaction has the unit, dm6 mol-2. 13 The graphs below show how the percentage of gaseous products present at equilibrium vary with temperature and pressure. Which one of the following reactions could the graph represent? A H 2 (g) + I2 (g) 2HI (g) H = + 53 kJ mol-1 B N2O4 (g) 2NO2 (g) H = + 57 kJ mol-1 C N2 (g) + 3H2 (g) 2NH3 (g) H = - 92 kJ mol-1 D 2Fe (s) + 2 3 O2 (g) Fe2O3 (s) H = - 822 kJ mol-1 pressure T oC (T + 10) oC % products at equilibriu m

6 14 The pH of normal human blood is 7.4. Strenuous exercise can cause the condition called acidosis in which the pH falls. If the pH drops to 6.8, death may occur. How many times greater is the hydrogen ion concentration in blood at pH 6.8 compared with that at pH 7.4? A 0.6 B 2.0 C 4.0 D 8.0 15 If the rate of decay of a radioactive isotope decreases from 200 counts per minute to 25 counts per minute in 1 day, what is its half-life? A 2 hours B 4 hours C 6 hours D 8 hours 16 Fibre glass can be considered to be a mixture of ionic oxides and giant covalent oxides. Which of the following is not a constituent of fibre glass? A SO 2 B SiO2 C Na2O D MgO 17 Which of the following elements forms an insoluble oxide and a chloride which is readily hydrolysed? A magnesium B phosphorus C silicon D sodium 18 What is the total number of  (sigma) and  (pi) bonds in a methylacetylene molecule? HC C CH3 methylacetylene   A 4 4 B 5 3 C 6 2 D 7 1

7 0 19 Samples of the gases CH4 and Cl2 are mixed together and irradiated with light. Which compound is not produced in the reaction? A HCl B H2 C CH3Cl D CH2Cl2 20 Straight chain alkanes undergo cracking under high temperature and in the presence of a catalyst. Which of the following does not represent a correct cracking reacti