An impure sample of silver (1.5 g) is heated with S to form 0.124 g of Ag₂S. What was the percent yield of Ag₂S?

$\underset{2\mathrm{x}108 =216\mathrm{g}}{2\mathrm{Ag}}+\mathrm{S}\to \underset{248\mathrm{g}}{{\mathrm{Ag}}_2\mathrm{S}}$
216 g of Ag forms 248 g of Ag₂S
1.5 g of Ag forms $\frac{248}{216}\times 1.5=1.722 \mathrm{g} \mathrm{of} {\mathrm{Ag}}_2\mathrm{S}$
% yield of Ag₂S $=\frac{0.124}{1.722}\times 100=7.2 \mathrm{\%}$