Question

A 1.50 g sample of an ore containing silver was dissolved,and all the $A{g}^{+}$ was converted to 0.125 g $A{g}_{2}S$. What was the percentage of silver in the ore?

• A. 14.23%
• B. 8.27%
• C. 10.8%
• D. 7.2%

Answer 1

Answer: (D)

7.2%

Number of moles of $A{g}_{2}S=\frac{0.125g}{\text{Molecular weight of}A{g}_{2}S}=\frac{0.125}{247.8}=5\times {10}^{-4}mole$

Mass of silver$=5\times {10}^{4}mole\times 2\times 108=0.108g$

$\therefore$Percentage of silver in ore$=\frac{0.108}{1.5}\times 100=7.2\%$