Question

If a solution contained a substance of 4.67kg (molar mass of 34.6 g/mol) in 350mL, what is the molarity of the solution?

Answer 1

The molarity of a solution is the molar concentration of it.

It is calculated by:

$M=\frac{n}{V}$

Where n is the number of moles of the substance in the solution and V is the total volume of the solution.

The volume was given:

$V=350mL=0.350L$

And the number of moles we can calculate using the given mass and the molar mass:

$\begin{gathered} m=4.67\operatorname{kg}=4670g \\ MM=34.6g/mol \end{gathered}$

So:

$\begin{gathered} MM=\frac{m}{n} \\ n=\frac{m}{MM}=\frac{4670g}{34.6g/mol}=134.97\ldots mol \end{gathered}$$M=\frac{134.97\ldots mol}{0.350L}=385.63\ldots mol/L\approx386mol/L$

Thus, the molarity is approximately 386 mol/L.