1.The activity coefficient of zinc in liquid zinc-copper alloys in the temperature range 1,070 – 1,300K can be expressed as follows : RTlny, = -31,6OON& where R = 8.3 14 J moT’K-‘. Calculate the vapour pressure of Zn over a Cu-Zn binary solution of N, = 0.3 at 1,280K. The vapour pressure of pure liquid zinc is given by l0gP = – 4J620 – 2.26iogT+ 12.34 (ton)
2. A container having three compartments contains 1 mole of gas A, 2 moles of gas B and 3 moles of gas C, respectively, at the same temperature and pressure (298K and 1 am). The partitions are lifted and the gases are allowed to mix. Calculate the change in the Gibbs free energy G’? Assume the gases behave ideally.
