## Chemistry: The Molecular Science (5th Edition)

$30\%$ $H_{2}O_{2}$ means that 100.g solution contains 30.0g $H_{2}O_{2}$. Molar mass of $H_{2}O_{2}=34.0147\,g/mol$ Number of moles $n= \frac{mass\,in\,grams}{Molar\,mass}$ $=\frac{30.0\,g}{34.0147\,g/mol}=0.8819716\,mol$ Volume of the solution V= $\frac{mass\,of\,the\, solution}{Density\,of\, the\, solution}=\frac{100\,g}{1.11\,g/mL}$ $=90.09\,mL=0.09009\,L$ Molarity=$\frac{n}{V}=\frac{0.8819716\,mol}{0.09009\,L}=9.79\,M$