Define the term lattice energy. ........................................................................................................................................................... .........................................................................................................................................................

1. (a)(i)Define the term lattice energy. ........................................................................................................................................................... .........................................................................................................................................................[2]
2. (a)(ii)Use the following data to calculate a value for the enthalpy change of solution of copper(II) chloride, CuCl2(s). You might find it helpful to construct an energy cycle. enthalpy change of hydration of Cl- = −378 kJ mol-1 enthalpy change of hydration of Cu2+ = −2099 kJ mol-1 lattice energy of CuCl2(s) = -2824 kJ mol-1 enthalpy change of solution of CuCl2(s) = .............................................................. kJ mol-1[2]
3. (a)(iii)The enthalpy change of hydration of Ca2+ is –1579 kJ mol-1. Use the Data Booklet to suggest why there is a big difference in the values of ∆Hhyd for Ca2+ and Cu2+. ........................................................................................................................................................... ........................................................................................................................................................... .........................................................................................................................................................[2]
4. (b)(i)Identify the substances formed at the anode and at the cathode during the electrolysis of saturated CaCl2(aq). at the anode ............................................................................................................................... at the cathode ............................................................................................................................[1]
5. (b)(ii)Calcium can be produced by the electrolysis of molten calcium chloride, CaCl2(l). Calculate the mass, in g, of Ca formed when a current of 0.75A passes through CaCl2(l) for 60 minutes. [Ar: Ca, 40.1] mass of Ca = .............................................................. g[2]
6. (c)(i)Explain what is meant by the term entropy of a system. .........................................................................................................................................................[1]
7. (c)(ii)Place one tick (✔) in each row of the table to show the sign of each entropy change, ∆S. process ∆S is negative ∆S is zero ∆S is positive NaCl dissolving in water water solidifying to ice[1]
8. (c)(iii)The evaporation of one mole of water has a standard Gibbs free energy change, ∆G°, of +8.6 kJ at 25 °C. Sketch a graph on the axes to show how ∆G changes for this process between 25°C and 150°C at 101 kPa. [Figure showing axes for ∆G vs temperature][2]
9. (d)The reaction between A and B is feasible at low temperatures but is not feasible at high temperatures. A + B ⇌ C + D Deduce the signs of ∆H and ∆S for this reaction and explain why the feasibility changes with temperature. sign of ∆H = ............................................. sign of ∆S = ............................................. ........................................................................................................................................................... ...........................................................................................................................................................[2]