Answer
$C_{Ag} $= 87.90 at%
$C_{Cu} $= 12.10 at%
Work Step by Step
Given:
92.5 wt% Ag
7.5 wt% Cu
Solution:
$A_{Ag} = 107.87 g/mol$
$A_{Cu} = 63.55 g/mol$
Using Equation 4.6:
$C_{Ag} = \frac{C_{Ag}A_{Cu}}{C_{Ag}A_{Cu} +C_{Cu}A_{Ag}} \times 100 = \frac{(92.5)(63.55 g/mol)}{(92.5)(63.55 g/mol) + (7.5)(107.87)} \times 100 $= 87.90 at%
$C_{Cu} = \frac{C_{Cu}A_{Ag}}{C_{Ag}A_{Cu} +C_{Cu}A_{Ag}} \times 100 = \frac{(7.5)(107.87 g/mol)}{(92.5)(63.55 g/mol) + (7.5)(107.87)} \times 100 $= 12.10 at%