What is the molarity of a 17.0% by mass solution of sodium acetate, NaC2H3O2 (82.0 g/mol) in water? The density of the solution is 1.09 g/mL.

M = 2.26 M

Explanation:

In this case, we can use an expression real short and easy to understand to calculate the molarity of any solution if we know the density, %.

M = d * % * 1000 / 100 * MM (1)

The number 1000, comes from the fact that we are assuming that we have 1 liter of solution (or 1000 mL) and the 100 comes from the purity of the compound which it can be 100%.

Now with the given data, all you have to do is to replace the given data in the above expression to get the molarity:

M = 1.09 * 17 * 1000 / 100 * 82

M = 2.26 M