## Chemistry: The Central Science (13th Edition)

$3.82\;m\;Zn$
For ease of this calculation, we will assume 100 g sample. Recall that molality is mol solute / kg solvent. Find mass of Zn in the sample. $100\;g\;sample\times\;20\%\;Zn=20.0\;g\;Zn$ Find moles of Zn (molar mass = 65.38 g/mol) $\frac{20.0\;g\;Zn}{}(\frac{1\;mol}{65.38\;g})=0.306\;mol\;Zn$ Find molality. $\frac{0.306\;mol\;Zn}{100\;g\;sample}=3.82\;m\;Zn$