Formula from Chapter 3: chemical amount of a solute
\(n_{\mathrm{solute}} = c_{\mathrm{solute}} \cdot V_{\mathrm{solution}}\)
You can use this if: there is a solution (homogeneous mixture)
\(n_{\mathrm{solute}}\) \(= 0.513\ \mathrm{mol}\)
\(V_{\mathrm{solution}}\) \(= 0.750\ \mathrm{L}\)
\(c_{\mathrm{solute}}\) \(= \dfrac{n_{\mathrm{solute}}}{V_{\mathrm{solution}}}\)
\(\ \ \ =\dfrac{0.513\ \mathrm{mol}}{0.750\ \mathrm{L}}\)
\(\ \ \ =0.684\ \frac{\mathrm{mol}}{\mathrm{L}}\)