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GCE JAN 2009 : (AS 1) General Chemistry

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Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2009 Chemistry assessing Module 1: General Chemistry ASC11 Assessment Unit AS 1 [ASC11] FRIDAY 16 JANUARY, MORNING TIME 1 hour 30 minutes. INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces provided at the top of this page. Answer all seventeen questions. Answer all ten questions in Section A. Record your answers by marking the appropriate letter on the answer sheet provided. Use only the spaces numbered 1 to 10. Keep in sequence when answering. Answer all seven questions in Section B. Write your answers in the spaces provided in this question paper. For Examiner s use only Question Marks Number Section A 1 10 Section B 11 INFORMATION FOR CANDIDATES The total mark for this paper is 100. Quality of written communication will be assessed in question 15(d)(ii). In section A all questions carry equal marks, i.e. two marks for each question. In Section B the figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. A Periodic Table of Elements (including some data) is provided. 4974 12 13 14 15 16 17 Total Marks Section A For each of the questions only one of the lettered responses (A D) is correct. Select the correct response in each case and mark its code letter by connecting the dots as illustrated on the answer sheet. 1 How many electrons are there in a calcium ion? A B C D 2 Which one of the following equations represents the second ionisation energy for barium? A B C D 3 18 20 22 40 Ba(s) Ba(g) Ba+ (s) Ba+ (g) Ba2+(g) + 2e Ba2+(g) + 2e Ba2+(g) + e Ba2+(g) + e Which one of the following shows the trend in electronegativity values of the elements in the Periodic Table? Across a Period A decrease decrease increase C increase decrease D increase increase The element astatine lies immediately below iodine in the Periodic Table and is likely to A B C D 4974 decrease B 4 Down a Group be pale yellow. be a volatile liquid at room temperature and pressure. form a hydride which dissolves in water to give an acidic solution. oxidise iodide ions to iodine. 2 [Turn over 5 If the price of one tonne (1000 kg) of sulphur is 160, what is the cost (to the nearest pound) of the sulphur needed to make one tonne of sulphuric acid, H2SO4? A B C D 6 Which one of the following does not obey the octet rule? A B C D 7 52 98 160 490 beryllium chloride carbon dioxide nitrogen oxygen The orbitals of a nitrogen atom may be represented as shown. 1s 2s 2p Which one of the following diagrams represents the arrangement of electrons in the ground state of the nitrogen atom? A B C D 4974 3 [Turn over 8 Potassium iodide is formed when potassium is warmed in iodine vapour. Which one of the following describes the bonding in the three species? potassium potassium iodide A ionic covalent ionic B metallic ionic covalent C covalent covalent ionic D 9 iodine metallic covalent ionic Which one of the following has a bond angle of 109.5 ? A B C D BeCl2 BF3 CH4 CO2 10 Which one of the following ions has the largest radius? A B C D 4974 F Mg2+ Na+ O2 4 [Turn over Section B Examiner Only Marks Remark Answer all seven questions in the spaces provided. 11 Metal ions are responsible for the flame colours produced by fireworks. Complete the table below by inserting the flame colour for each metal ion. metal ion flame colour barium potassium sodium [3] 12 (a) Draw the shape of an s orbital. [1] (b) Draw the shape of a p orbital. [1] (c) Write the electronic configuration of a carbon atom in terms of s and p electrons. _______________________________________________________ [1] 4974 5 [Turn over 13 Rocket fuels need to supply a large amount of energy, yet have a low mass i.e. a high power to weight ratio. Examiner Only Marks Remark One potential reaction is that of fluorine with diborane (a boron hydride). HH H B BH HH diborane B2H6(g) + 6F2(g) 6HF(g) + 2BF3(g) (a) Calculate the enthalpy change when one mole of diborane reacts completely with fluorine given the following bond enthalpies. bond kJ mol 1 F B B H B 158 389 293 566 627 F H B F F _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] (b) The bond enthalpy of hydrogen fluoride is 566 kJ mol 1 whereas that of hydrogen iodide is 299 kJ mol 1. State what would be observed when hydrogen fluoride and hydrogen iodide are heated. _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] 4974 6 [Turn over (c) Both HF and BF3 are gases at room temperature and pressure. Calculate the total volume of gas produced at 20 C and one atmosphere pressure by the complete reaction of 7.0 g of diborane with fluorine. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] (d) State and explain the shape of the boron trifluoride molecule. _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] 4974 7 [Turn over 14 Silver occurs in nature as the sulphide and as the chloride. Although less malleable and less ductile than gold, the thermal and electrical conductivities of silver are greater than those of any other metal. Examiner Only Marks Remark (a) (i) Explain what is meant by the term malleability. _____________________________________________________ ___________________________________________________ [2] (ii) Explain what is meant by the term ductility. _____________________________________________________ ___________________________________________________ [2] (iii) Explain how silver is able to conduct electricity. _____________________________________________________ ___________________________________________________ [2] (b) Silver hardly dissolves in hydrochloric acid and the usual method of preparing silver chloride is to add a soluble metal chloride to a soluble silver salt. (i) Name a soluble metal chloride. ___________________________________________________ [1] (ii) Name a soluble silver salt. ___________________________________________________ [1] (iii) Write an ionic equation for the reaction of the soluble metal chloride with the soluble silver salt. ___________________________________________________ [1] 4974 8 [Turn over (c) Silver chloride is virtually insoluble in water. Its solubility has been estimated at 0.4 mg in 250 cm3 of water at 20 C. Examiner Only Marks Remark (i) Calculate the molar mass of silver chloride. ___________________________________________________ [1] (ii) Calculate the number of moles of silver chloride in 0.4 mg. _____________________________________________________ ___________________________________________________ [1] (iii) Calculate the solubility of silver chloride in moles per litre. _____________________________________________________ ___________________________________________________ [1] (iv) Name a solution that will dissolve silver chloride. ___________________________________________________ [1] (v) Silver chloride is a white solid which is affected by light. Describe and explain the effect of light on silver chloride. _____________________________________________________ ___________________________________________________ [2] 4974 9 [Turn over 15 Bromine was discovered in the residues from the manufacture of sea salt at Montpellier, France. The residues contain magnesium bromide. Examiner Only Marks Remark The addition of chlorine liberates bromine. (a) (i) Write an equation for the reaction of chlorine with magnesium bromide. ___________________________________________________ [2] (ii) Using electron transfer, explain why this can be considered to be redox reaction. _____________________________________________________ _____________________________________________________ ___________________________________________________ [3] (b) Bromine, Br2, is a liquid at room temperature. Liquid bromine has a high density: 1 mol of bromine, Br2, occupies 51 cm3. Calculate the density of bromine in g cm 3. _________________________________________________________ _______________________________________________________ [2] (c) Bromine is miscible with organic (non-aqueous) solvents, but its solubility in water is more limited. The aqueous solution is known as bromine water. (i) Name a non-aqueous solvent that dissolves bromine. ___________________________________________________ [1] (ii) Compare the solubilities of bromine and iodine in water. _____________________________________________________ ___________________________________________________ [2] 4974 10 [Turn over (iii) Describe what would be observed if bromine water was added to concentrated solutions of sodium chloride and sodium iodide respectively. Examiner Only Marks Remark sodium chloride ___________________________________________________ [1] sodium iodide ___________________________________________________ [1] (d) The concentration of bromine in solution can be measured by reacting it with excess potassium iodide and the liberated iodine determined by titration with sodium thiosulphate solution. (i) Write an equation for the reaction of sodium thiosulphate with iodine. ___________________________________________________ [2] (ii) Describe, with practical details, how this titration would be carried out. Assume all the apparatus is clean and dry. Details of calculations are not required. _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ ___________________________________________________ [5] Quality of written communication 4974 [2] 11 [Turn over 16 Oxalic acid (ethanedioic acid) is a weak dicarboxylic acid. It is similar to acetic acid (ethanoic acid) which is a monocarboxylic acid. COOH Examiner Only Marks Remark CH3COOH COOH oxalic acid acetic acid (a) Suggest the meaning of the term dicarboxylic acid. _________________________________________________________ _______________________________________________________ [2] (b) Both of these acids react with alkalis. Write the equation for the reaction of oxalic acid with excess sodium hydroxide. _______________________________________________________ [2] (c) Weak acids such as oxalic acid can be titrated with strong alkalis using phenolphthalein as indicator. State the colour of phenolphthalein in alkaline and acidic solution. alkali __________________________________________________ [1] acid ___________________________________________________ [1] 4974 12 [Turn over (d) If oxalic acid reacts with a small amount of phosphorus pentachloride a mixture of gases is produced: Examiner Only Marks Remark How could you show that hydrogen chloride was a product? _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] (e) Oxalic acid reacts with excess phosphorus pentachloride to give oxalyl chloride which has the following percentage composition by mass. element % composition carbon 18.9 chlorine 55.9 oxygen 25.2 Calculate the empirical formula of oxalyl chloride. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] 4974 13 [Turn over 17 Hydrogen has three naturally occurring isotopes: protium 1H, deuterium 2H and tritium 3H. Examiner Only Marks Remark (a) Draw an atom of tritium showing and labelling all the sub-atomic particles present. [2] (b) The relative atomic mass of hydrogen is 1.0079. Explain which one of the hydrogen isotopes is the most abundant in nature. _________________________________________________________ _______________________________________________________ [2] 4974 14 [Turn over (c) When subjected to an electrical discharge, atomic hydrogen emits electromagnetic radiation due to electron transitions between energy levels. The line emission spectrum of atomic hydrogen in the visible region is shown below. Examiner Only Marks Remark frequency (i) To which energy level do electrons return to produce lines in the visible region? ___________________________________________________ [1] (ii) The lowest frequency line in the visible region has a frequency of 4.568 1014 s 1. Calculate the energy in kJ mol 1, associated with this frequency. _____________________________________________________ _____________________________________________________ _____________________________________________________ ___________________________________________________ [3] (iii) Explain why the lines in the emission spectrum converge. _____________________________________________________ ___________________________________________________ [2] 4974 15 [Turn over (d) It is possible to obtain pure deuterium oxide, D2O, from sea water. Deuterium oxide boils at 101.4 C compared to 100.0 C for water. Examiner Only Marks Remark (i) Name the two types of intermolecular forces which exist between water molecules. _____________________________________________________ ___________________________________________________ [2] (ii) Draw a dot and cross diagram to show the bonding in deuterium oxide, D2O, showing all the outer shell electrons. [2] (iii) Deuterium oxide can combine with deuterium ions, D+, to form D3O+. Write an equation for this reaction. ___________________________________________________ [1] (iv) Name the type of bond formed between the oxygen atom and the deuterium ion. ___________________________________________________ [1] THIS IS THE END OF THE QUESTION PAPER 4974 16 [Turn over Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 935-061-1

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Additional Info : Gce Chemistry January 2009 Assessment Unit AS 1Module 1: General Chemistry
Tags : General Certificate of Education, A Level and AS Level, uk, council for the curriculum examinations and assessment, gce exam papers, gce a level and as level exam papers , gce past questions and answer, gce past question papers, ccea gce past papers, gce ccea past papers

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