# Question #63908

##### 1 Answer

Your solution contains **0.32 g** of sodium chloride.

A percent concentration by mass expresses the ratio between the mass of the solute, in your case sodium chloride, and the *total mass* of the solution, multiplied by 100.

So, you know that your sample weighs **16 g** and that it's **2% m/m** sodium chloride. You can use this data to determine how many grams of sodium chloride must be present in that much solution by

Think of it like this: you know the mass of sodium chloride represents **2%** by mass of a solution. To get from **2%** to **100%** you need to multiply by **50**, so the mass of sodium chloride can be determined by *dividing* the total mass by 50.

For example, if you have a **25% m/m** solution that has a total mass of 16 g, the mass of sodium chloride would be **4 g**.

That happens because you need to divide 100% by **4** to get to 25%, so divide the total mass by 4 to get the mass of the solute.