Question

What mass of solute is there in 150 mL of a 0.250 mol/L solution of FeNO3?

Answer 1

$\begin{aligned} \textsf{Molar Concentration (C) }&= 0.250\ mol/L\\ \textsf{Volume (V) } &= 150mL = 0.150L\\ \\ \textsf{number of moles (n) }&= C × V\\ &= 0.250 × 0.150\\ &= 0.0375 moles \end{aligned}$

$\begin{aligned} \textsf{mass of solute } &= \textsf{number of moles } × \textsf{molar mass}\\ \\ \textsf{molar mass of }Fe({NO_3})_3 &= 56 + 3(14 + 48) = 242\ g/mol\\ \\ \therefore \textsf{mass of solute } &= 0.0375 × 242\\ &= 9.075g \end{aligned}$