For an alloy that consists of 93.1 g copper, 111.7 g zinc, and 4.0 g lead, what are the concentrations of (a) Cu, (b) Zn, and (c) Pb in weight percent? The atomic weights of Cu, Zn, and Pb are 63.54, 65.39, and 207.2 g/mol, respectively.

(a) weight percent of Cu = 44.59%

(b) weight percent of Zn = 53.49%

(c) weight percent of Pb = 1.91%

Explanation:

Given: Alloy contains - Cu=93.1 g, Zn=111.7 g, Pb=4.0 g

Therefore, the total mass of the alloy (m) = mass of Cu (m₁) + mass of Zn (m₂) + mass of Pb (m₃)

m = 93.1 g + 111.7 g + 4.0 g = 208.8 g

(a) weight percent of Cu = (m₁ : m) * 100% = (93.1 g : 208.8 g) * 100% = 44.59%

(b) weight percent of Zn = (m₂ : m) * 100% = (111.7 g : 208.8 g) * 100% = 53.49%

(c) weight percent of Pb = (m₃ : m) * 100% = (4.0 g : 208.8 g) * 100% = 1.91%