CIE Nov 2016 v3 Paper 2 Q3

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The elements in Group 2 and their compounds show various trends in their physical and chemical properties. (a) The graph below shows the radius values of the atoms and 2+ ions of the elements in Group 2. PMT radius / nm 0.25 0.20 0.15 0.10 0.05 Be Mg Sr Ca element Ba Ra (i) Explain why both lines show a steady increase in the values of the radii down the group.[2] (ii) State and explain which line represents the atomic radii and which represents the ionic radii.[2] (b) L is a salt of a Group 2 element M. When L is heated strongly a brown gas is observed and a white solid remains. The white solid dissolves in water to form a colourless solution of the metal hydroxide M(OH)2. Addition of dilute sulfuric acid to this colourless solution produces a dense white precipitate. (i) Identify the anion in salt L.[1]UCLES 2016 9701/23/O/N/16<br /> PMT (ii) Identify the element M and write an ionic equation for the formation of the white precipitate with sulfuric acid. M =equation[1] (iii) Give the formula of salt L and use it to write an equation for the thermal decomposition of salt L. formula of salt Lequation[2] (c) Calcium carbonate and calcium hydroxide can both be used in agriculture to neutralise acidic soils. (i) Write ionic equations for the neutralisation of acid by each of calcium hydroxide and calcium carbonate. calcium hydroxidecalcium carbonate[2] (ii) Suggest and explain why calcium carbonate is a better choice than calcium hydroxide for this purpose in areas of high rainfall.[2] (d) Magnesium reacts with both cold water and steam. Give the formula of the magnesium-containing product of each of these reactions. with cold waterwith steam[2] [Total: 14]UCLES 2016 9701/23/O/N/16 [Turn over<br />

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