Question

$4.6c{m}^3$ of methyl alcohol is dissolved in $25.2$g of water. Calculate $\%$ by mass of methyl alcohol.

(Given density of methyl alcohol = $0.7952gc{m}^{-3}$ and $C=12,H=1,O=16$)

Answer 1

Given: $W_1=25.2g$ $V_{\left(C{H}_{3}OH\right)}=4.6c{m}^3$

$P_{\left(C{H}_{3}OH\right)}=0.7952g/c{m}^3$

Molar mass= $32g/mol$

$\therefore W_2$= Density $\times$ volume

$=0.7952\times 4.6$

$=3.658g$

% by mass=$\left(\frac{3.658}{25.2+3.658}\right)\times 100$

$=\frac{3.658}{28.8586}\times 100=12.67$%