OCR A Jun 2010 Paper 5 Q1

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Answer all the questions. Lattice enthalpy can be used as a measure of ionic bond strength. Lattice enthalpies are determined indirectly using an enthalpy cycle called a BornHaber cycle. The table below shows the enthalpy changes that are needed to determine the lattice enthalpy of magnesium chloride, MgCl 2. letter enthalpy change 1st electron af nity of chlorine 1st ionisation energy of magnesium atomisation of chlorine formation of magnesium chloride atomisation of magnesium 2nd ionisation energy of magnesium lattice enthalpy of magnesium chloride energy / kJ mol1 349 +736 +150642 +76 +1450OCR 2010<br />
 (a) On the cycle below, write the correct letter in each empty box. Mg2+(g) + 2Cl(g) + 2e Mg+(g) + 2Cl(g) + e Mg2+(g) + 2Cl (g) Mg(g) + 2Cl(g) Mg(g) + Cl2(g) Mg(s) + Cl2(g) (b) Use the BornHaber cycle to calculate the lattice enthalpy of magnesium chloride. MgCl2(s) [3] answer =kJ mol1 [2] (c) Magnesium chloride has stronger ionic bonds than sodium chloride. Explain why.[3]OCR 2010 [Total: 8] Turn over<br />

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