CIE Nov 2015 v1 Paper 4 Q1

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Section A Answer all the questions in the spaces provided. (a) Calcium has atomic number 20. Complete the electronic structures for a calcium atom, 1s22s22p6 calcium ion in the +2 oxidation state. 1s22s22p6 PMT [1] (b) Calcium nitrate, Ca(NO3)2, is used in fertilisers and can be prepared by an acid-base reaction. Write an equation for the preparation of calcium nitrate by an acid-base reaction.[1] (c) (i) When anhydrous calcium nitrate is heated strongly, it decomposes to leave a white solid. Identify this white solid and suggest another observation for this reaction.[1] (ii) The ease of thermal decomposition of the Group II nitrates decreases down the group. Explain this trend.[2]UCLES 2015 9701/41/O/N/15<br /> PMT (d) (i) What is meant by the term standard enthalpy change of hydration,[2] (ii) Use the following data to calculate the lattice energy, You may find it helpful to construct an energy cycle. , of calcium nitrate, Ca(NO3)2(s). enthalpy change (Ca2+(g)) (NO3 (g)) value 1650 kJ mol1 314 kJ mol1 enthalpy change of solution for Ca(NO3)2(s) 19 kJ mol1 Ca(NO3)2(s) =kJ mol1 [3] (e) The standard enthalpy change of hydration for Ba2+, (Ba2+(g)), is 1305 kJ mol1. Suggest an explanation for why the the Ca2+ ion. of the Ba2+ ion is less exothermic than the of[2]UCLES 2015 9701/41/O/N/15 [Total: 12] [Turn over<br />

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