Question

In 100 ml alcool etilic (d=0.80 g/cm^3) s-au dizolvat 8.5 g iod.Care este concentratia procentuala a solutiei obtinute?

Answer 1

$1~ml=1~cm^3 \\ \\ 100~ml=100~cm^3 \\ \\ m_{alcool}=\mathcal{V}_{alcool}\cdot\rho_{alcool}=100\cdot0,8=80~g \\ \\ m_{solutie}=m_{alcool}+m_{iod}=88,5~g \\ \\ concentratia=\frac{m_{iod}}{m_{solutie}}=\frac{8,5}{88,5}=\frac{17}{177}$
Pentru a afla concentratia procentuala inmultim fractia cu 100
$=\frac{1700}{177}\approx9,604\%$