Question

An ore contains 1.34% of the mineral argentite, $Ag_2S$, by mass How many gram of this ore would have to be processed in order to obtain 1.00 g of pure solid silver, Ag ?

• A. 74.6 g
• B. 85.7 g
• C. 107.9 g
• D. 134.0 g

Answer 1

Answer: (B)

85.7 g

Answer 2

$100 \,g$ ore $\equiv 1.34\,g$ of $Ag_{2}S$ Molar mass of $Ag_{2}S=248\,g\,mol^{-1}$ $248\, g$ of $Ag_{2}S \equiv 2\times 108\,g$ of $Ag=216\,g$ of $Ag\, 1.00\, g$ of $Ag$ $=1.00g of Ag\times\left(\frac{248\,Ag_{2}\,S}{216\, g\,Ag}\right)\times\left(\frac{100\,g ore}{1.34\,g\,Ag_{2} S}\right)$ $=85.68\,g$ $=85.7\,g$