## Chemistry and Chemical Reactivity (9th Edition)

$17.7\%$
For 1 mol of mixture: $0.20\ mol\ hexane \times 86.178\ g/mol=17.24\ g$ $0.80\ mol\ hexane \times 86.178\ g/mol=80.16\ g$ Mass fraction of hexane: $\dfrac{17.24}{17.24+80.16}=0.177\ or\ 17.7\%$