PJC H2 Chem 2013 Prelim P1 QP Soln

PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION HIGHER 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 27 September 2013 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, Centre number and index 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. This document consists of 16 printed pages. Name: Index No.: CT Group: 12 Name: Index No.: 947

2 © PJC 2013 9647/01/JC2 PRELIM/2013 Section A For each question, there are f our possible answers labelled A, B, C and D. Choose the one you consider to be correct. 1 Carbon disulfide, CS 2, is a volatile flammable liquid used in the manufacture of cellophane. On combustion, CS 2 is oxidised as follows. CS2(g) + 3O2(g) → CO2(g) + 2SO2(g) A 20 cm 3 sample of carbon disulf ide is ignited with 100 cm 3 of oxygen. The final volume of gas after burning is treated with an excess of aqueous alkali. What percentage of this final volume remains after treatment with the alkali? A 20% B 40% C 60% D 80% 2 25.0 cm 3 of 0.05 mol dm3 KClO4(aq) required 50.0 cm 3 of 0.20 mol dm3 TiCl3 (aq) to reach end-point. Given that titanium( III) is oxidised to titanium( IV) in this reaction, which of the following formulae correctly represents the reduction product of the ClO 4 - ion? A Cl B ClO2  C ClO3  D OCl 3 The successive ionisation energies, in kJ mol1, of an element X are given below. 870 1800 3000 3600 5800 7000 13200 Which of the following can be inferred from the data provided? A X has no unpaired valence electrons in its atomic structure. B X has a lower first ionisation energy than the element preceding it in the Periodic Table. C X is likely to form an ionic compound with a non-metallic element. D X would achieve noble gas configuratio n after removing all its first seven electrons. 948

3 © PJC 2013 9647/01/JC2 PRELIM/2013 4 A 2 g sample of hydrogen at temperature T and of volume V exerts a pressure p. Deuterium, H2 1 , is an isotope of hydrogen. Which of the following would also exert a pressure of p at the same temperature T? A a mixture of 1 g of hydrogen and 1 g of deuterium of total volume V B a mixture of 1 g of hydrogen and 2 g of deuterium of total volume 2V C a mixture of 2 g of hydrogen and 2 g of deuterium of total volume 2V D a mixture of 2 g of hydrogen and 4 g of deuterium of total volume 2V 5 In which of the following pairs is the bond angle of the second molecule or ion greater than that of the first? A NO 2 +, NO2  B SO4 2, SO3 2 C BrF3, ClF3 D PH3, AsH3 6 Which of the following statements about the properties associated with ionic and covalent bonds is correct? A A covalent compound can be an electrolyte. B The only covalent compounds with high melting points are those in which hydrogen bonds occur. C Ionic bonds and covalent bonds cannot both occur in the same compound. D Any covalent compound that contains both oxygen and hydrogen in its molecules forms hydrogen bonds. 7 The enthalpy change of formation of H 2S(g) and H 2O(l) are -21 kJ mol 1 and -286 kJ mol 1 respectively and the enthalpy change of vaporisation of water is +41 kJ mol1. What is the enthalpy change of reaction for the following process? H2S(g) + ½O2(g) → H2O(g) + S(s) A -224 kJ mol1 B -266 kJ mol1 C -306 kJ mol1 D -348 kJ mol1 949

4 © PJC 2013 9647/01/JC2 PRELIM/2013 8 A methane-oxygen fuel cell is built using a 1 mol dm 3 hydrochloric acid as the electrolyte. The overall equation for the reaction occurring in the fuel cell is: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) What would be the change in pH of the solution around each electrode when current flows? cathode anode A increases increases B increases decreases C decreases increases D decreases decreases 9 A voltaic cell is made up of the Mg 2+/Mg half-cell and the Fe3+/Fe2+ half-cell. Which one of the following statements is correct? A The Mg2+/ Mg half-cell is the positive electrode. B Increasing the temperature has no effect on the e.m.f. of the cell. C Addition of NaOH(aq) to the Mg2+/ Mg half-cell decreases the e.m.f. of the cell. D Addition of water to the Fe3+/Fe2+ half-cell has no effect on the e.m.f. of the cell. 950

5 © PJC 2013 9647/01/JC2 PRELIM/2013 10 The graphs below show the variation of the percentage of gaseous products present at equlibrium, with temperature and pressure. Which one of the following systems could the graphs represent? A N2(g) + 3H2(g) ⇌ 2NH3(g) H = –92 kJ mol1 B 3O2(g) + 4NH3(g) ⇌ 2N2(g) + 6H2O(g) H = –1248 kJ mol1 C 2N2(g) + O2(g) ⇌ 2N2O (g) H = +82 kJ mol1 D CO2(g) + C(s) ⇌ 2CO (g) H = +173 kJ mol1 11 Which of the following statements about acids, bases and salts is correct? A 10 cm 3 of 0.10 mol dm 3 of sodium hydroxide reacts with 5 cm 3 of 0.10 mol dm3 ethanoic acid to produce an alkaline buffer. B 10 cm 3 of 0.10 mol dm 3 of ammonia reacts with 5 cm 3 of 0.10 mol dm 3 hydrochloric acid to produce an alkaline buffer. C 0.10 mol dm3 of aqueous sodium ethanoate has lower pH than 0.10 mol dm -3 of aqueous ammonium chloride. D 0.10 mol dm3 of ethanoic acid has higher pH than 0.10 mol dm 3 of aqueous sodium ethanoate. 12 Which statement explains the observations that magnesium hydroxide dissolves in ammonium chloride, but not in aqueous sodium chloride? A Ammonium hydroxide is first formed, and then ac ts through a common ion effect. B The ammonium ion changes the solubility product of Mg(OH)2. C NH4Cl dissociates less fully than NaCl. D The NH4 + ion acts as an acid. pressure % products at equilibrium (T + 10) oC T oC 951

6 © PJC 2013 9647/01/JC2 PRELIM/2013 13 In the reaction between aqueous s odium thiosulfate and dilute acid, the reaction is found to be first order with respect to acid at low concentrations of acid, but zero order with respect to acid when the acid concentration is high. Which graph represents the experimental results? A [acid] [rate] B [acid] [rate] C [acid] [rate] D [acid] [rate] 14 A chemical plant illegally dumped some radi oactive waste in a landfill. This waste composed of two radioactive isotopes M and N in the proportion 4:1. The decay of radioactive isotopes follows first- order kinetics. The half-life of M is 2 days whereas that of N is 4 days. By the time the authorit ies found out about this illegal dumping and analysed a sample of the waste, they found equal amounts of M and N. How long was the waste in the landfill before the authorities arrived? A 2 days B 4 days C 8 days D 16 days 15 P, Q and R are elements of the th ird period of the Periodic Table. The oxide of P is amphoteric, the oxide of Q is basic and oxide of R is acidic. What is the order of increasing atomic radius? A R P Q B Q P R C R Q P D Q R P 952

7 © PJC 2013 9647/01/JC2 PRELIM/2013 16 Magnesium oxide, a refractory ma terial, is used in the lining of blast furn