CIE Jun 2013 v3 Paper 4 Q3

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Examiners For Use (a) (i) What is meant by the density of a substance?(ii) Use data from the Data Booklet to explain why the density of iron is greater than that of calcium.[3] (b) In general, reactions of the compounds of transition elements can be classi ed under one or more of the following headings. acid-base ligand exchange precipitation redox Choose the most suitable heading to describe each of the following reactions, by placing a tick ( ) in the appropriate column in the table below. Only one tick should be placed against each reaction. (cid:22) reaction acid-base ligand exchange precipitation redox [Cu(H2O)6]2+ + 4NH3[Cu(NH3)4]2+ + 6H2O [Cu(H2O)6]2+ + 4HCl[CuCl 4]2 + 4H+ + 6H2O 2FeCl 2 + Cl 22FeCl 3 [Fe(H2O)6]2+ + 2OHFe(OH)2 + 6H2O 2Fe(OH)2 + O2 + H2O2Fe(OH)3 CrO3 + 2HClCrO2Cl 2 + H2O Cr(H2O)3(OH)3 + OH[Cr(H2O)2(OH)4] + H2O [Cr(OH)4] + 1H2O2 + OHCrO4 2 + 4H2OUCLES 2013 9701/43/M/J/13 [8]<br /> Examiners For Use (c) Alloys of aluminium, titanium and vanadium are used in aerospace and marine equipment, and in medicine. When a powdered sample of one such alloy is heated with an excess of aqueous NaOH, only the aluminium reacts, according to the following equation. 2Al (s) + 2OH(aq) + 6H2O(l)2[Al (OH)4](aq) + 3H2(g) Reacting 100 g of alloy in this way produced 8.0 dm3 of hydrogen, measured under room conditions. Calculate the percentage by mass of aluminium in the alloy. percentage =% [3] [Total: 14]UCLES 2013 9701/43/M/J/13 [Turn over<br />

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