Question

A 20.0 mL sample of a NaCL solution has a mass of 21.040 g. After the solution is evaporated to dryness, the dry salt residue has a mass of 4.348g. Calculate the following concentrations for the NaCl solutions. C) molarity

Answer 1

you know that there was 4.348g of NaCL in solution.
to find morality you need to understand this:
\[M=\frac{moles}{L}\]
convert 4.348g to moles of NaCL
and divide it by your conversion of 20.0 mL to L