Concentration of aqueous solutions

Exercise 3

    

Calculate the mass of nitric acid in $125\;g$ of a $17.45\% $ solution

Let be $S$ the solution. $\%_{HNO_3}$ $=$ $17.45$ $\frac{m_{HNO_3}\cdot 100}{m_S}$ $=$ $17.45$ $m_{HNO_3}$ $=$ $\frac{17.45\cdot 125}{100}$ $=$ $2.18 \cdot 10^1\;g$