Question

A solution contains 25% by mass methanol, 25% by mass acetone and 50% by mass water. Calculate the mole fraction of each component.

Answer 1

assume that the total mass is 100g
$$\begin{gathered} molesmethanol=\frac{25}{32}=0.78\text{mol} \\ \text{moles acetone}=\frac{25}{58}=0.43\text{mol} \\ \text{moles water}=\frac{50}{18}=2.78\text{mol} \\ t\text{otal moles}=4 \\ \text{Mole fraction} \\ \text{methanol}=\frac{0.78}{4}=0.2 \\ \text{acetone}=\frac{0.43}{4}=0.1 \\ \text{water}=\frac{2.78}{4}=0.7 \end{gathered}$$