Find volume (in ml) of 0.3 M solution of sodium chloride containing exactly 3.0g of sodium chloride.

Answer 1

mols = grams NaCl/molar mass NaCl
You know grams and molar mass, solve for mols.

Now use the definition of M.
M = mols/L
You know M, you know mols, solve for L and convert to mL.