9701_m17_qp_22 - revisedeck

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The table shows information about some of the elements in the third period. element Na Mg Al P S Cl atomic radius / nm 0.186 0.160 0.143 0.110 0.104 0.099 radius of most common ion / nm 0.095 0.065 0.050 0.212 0.184 0.181 maximum oxidation number of the element in its compounds +1 +7 Complete the table to show the maximum oxidation number of each element in its compounds. Explain why the atomic radius of elements in the third period decreases from Na to Cl. The radius of the most common ion of Mg is much smaller than the radius of the most common ion of S. Identify both ions and explain the difference in their radii. Phosphorus is a non-metal in the third period. It reacts vigorously with excess oxygen but slowly with chlorine. Some reactions of phosphorus are shown. phosphorus Aexcess O2reaction 1 Cl 2reaction 2 PCl 5+ HCl Bwater Write an equation to represent reaction 1, the formation of compound A. Give two observations you could make in reaction 2. 1. 2. Name compound B. Cerium is a lanthanoid metal that shows similar chemical reactions to some elements in the third period. Most of cerium’s compounds contain Ce3+ or Ce4+ ions. Cerium shows the same structure and bonding as a typical metal. Draw a labelled diagram to show the structure and bonding in cerium. Cerium(oxide, CeO2, is a ceramic. Suggest two physical properties of cerium(oxide. 1. 2. A naturally occurring sample of cerium contains only four isotopes. Data for three of the isotopes are shown in the table. isotope 136Ce 138Ce 140Ce 142Ce relative isotopic mass 135.907 137.906 139.905 to be calculated percentage abundance 0.185 0.251 88.450 to be calculated The Ar of the sample is 140.116. Use these data to calculate the relative isotopic mass of the fourth isotope in this sample of cerium. Give your answer to three decimal places. relative isotopic mass =

9. The Periodic Table: chemical periodicity → 9.2. Periodicity of chemical properties of the elements in Period 3

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Hydrogen halides are compounds formed when halogens (Group 17 elements) react with hydrogen. The bond polarity of the hydrogen halides decreases from HF to HI. Some relevant data are shown in the table. hydrogen halide HF HCl HBr HI boiling point / °C –85 –67 –35 H–X bond energy / kJ mol–1 Explain the meaning of the term bond polarity. Suggest why the boiling point of HF is much higher than the boiling points of the other hydrogen halides. Describe and explain the relative thermal stabilities of the hydrogen halides. The equation for the preparation of hydrogen chloride using concentrated sulfuric acid is shown. H2SO4 + NaCl NaHSO4 + HCl Use the Brønsted-Lowry theory of acids and bases to identify the base and its conjugate acid in this reaction. Explain your answer. Brønsted-Lowry base (base-= conjugate acid (acid-= Explain why the reaction of concentrated sulfuric acid and sodium iodide is not suitable for the preparation of hydrogen iodide. Hydrogen chloride undergoes a reversible reaction with oxygen. 4HCl + O22Cl 2+ 2H2OThe reaction is carried out at 400 °C in the presence of a copper(chloride catalyst. Use the data in the table to calculate the overall enthalpy change of reaction. compound enthalpy change of formation / kJ mol–1 HCl –92 H2O–242 enthalpy change of reaction = kJ mol–1 State the type of catalyst used in this reaction. Explain how a catalyst is able to increase the rate of a chemical reaction. The reaction exists in dynamic equilibrium. The reaction was repeated at 1000 °C and the same pressure. State and explain the effect on the composition of the equilibrium mixture of the change in temperature. When 1.60 mol of HCl are mixed in a sealed container with 0.500 mol of O2 at 400 °C, 0.600 mol of Cl 2 and 0.600 mol of H2O are formed. The total pressure inside the container is 1.50 × 105 Pa. ● Calculate the amounts, in mol, of HCl and O2 in the equilibrium mixture. HCl = mol O2 = mol ● Calculate the mole fraction of Cl 2 and hence the partial pressure of Cl 2 in the equilibrium mixture. mole fraction of Cl 2 = pCl 2 = Pa In a separate experiment, an equilibrium reaction mixture was found to contain the four gases at the partial pressures shown in the table. gas HCl O2 Cl 2 H2O partial pressure / Pa 4.8 × 104 3.0 × 104 3.6 × 104 3.6 × 104 Kp = (pCl 2)2 × (pH2O)2 (pHCl )4 × pO2 Use this information and the expression given for Kp to calculate a value for Kp. State the units of Kp. Kp = units = The reaction is repeated without a catalyst. State the effect of this on Kp.

11. Group 17 → 11.2. The chemical properties of the halogen elements and the hydrogen halides

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A series of reactions starting from 1-bromobutane is shown. 1-bromobutane CH3(CH2)3CO2H HCN and KCN R reaction 1 OH–P polymer Q but-1-ene reaction 2 Draw the displayed formula of compound P. Identify the reagentand conditions for reactions 1 and 2. reaction 1 reaction 2 Draw the structure of the repeat unit of polymer Q. Complete the reaction scheme to show the mechanism of the reaction of 1-bromobutane with OH–to produce R. Include all necessary charges, dipoles, lone pairs and curly arrows and the structure of R. C H Br CH3CH2CH2 H –OH But-1-ene reacts with steam as shown to form a mixture of two structural isomers, S and T. S major product U T minor product reflux Cr2O7 2– / H+ but-1-ene + steam S can be oxidised with acidified potassiumdichromate(to form compound U. S and U both react with alkaline aqueous iodine. Identify the type of reaction that occurs when but-1-ene reacts with steam. State what can be deduced about the structure of S from its reaction with alkaline aqueous iodine. Explain why S is the major product of the reaction of but-1-ene with steam. Draw the skeletal formulae of S, T and U. S T U Write an equation to represent the oxidation of S to U by acidified potassium dichromate(. You should use [O] to represent the oxidising agent. CH3(CH2)3CO2H is a colourless liquid with an unpleasant odour. It reacts with methanol in the presence of an acid catalyst to produce an organic product V, which has a pleasant fruity smell. Name V. A student analysed CH3(CH2)3CO2H, methanol and V using infra-red spectroscopy. The spectra were returned to the student without labels. Identify which of the infra-red spectra, X, Y or Z, corresponds to V. compound CH3(CH2)3CO2H methanol V spectrum Explain your answer with reference to relevant features of the three spectra in the region above 1500 cm–1.

15. Halogen compounds → 15.1. Halogenoalkanes

14. Hydrocarbons → 14.2. Alkenes

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