7.15 Liquid brasses conform to the following relationship: RT in Yzn -5000 2 Cu where and T are in cal/deg/mole and K respectively. The vapour pres- sures of pure copper and pure zinc (in mm Hg) are given as 1og pcu 17520 - 1.21 log T + 13.21, 6850 and 10g PZN 0.755 10g T + 11.24. Calculate (1) the vapour pressure of copper over a brass containing 40 atom% 7.15 Liquid brasses conform to the following relationship: RT in Yzn -5000 2 Cu where and T are in cal/deg/mole and K respectively. The vapour pres- sures of pure copper and pure zinc (in mm Hg) are given as 1og pcu 17520 - 1.21 log T + 13.21, 6850 and 10g PZN 0.755 10g T + 11.24. Calculate (1) the vapour pressure of copper over a brass containing 40 atom%