Find the phase compositions for the following alloys: (a) 15 wt% sn–85 wt% pb at 100°c (212°f) (b) 25 wt% pb–75 wt% mg at 425°c (800°f) (c) 85 wt% ag–15 wt% cu at 800°c (1470°f) (d) 55 wt% zn–45 wt% cu at 600°c (1110°f) (e) 1.25 kg sn and 14 kg pb at 200°c (390°f) (f) 7.6 lbm cu and 144.4 lbm zn at 600°c (1110°f) (g) 21.7 mol mg and 35.4 mol pb at 350°c (660°f) (h) 4.2 mol cu and 1.1 mol ag at 900°c (1650°f)

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o