# What do we mean by percentage concentration?

##### 1 Answer
Oct 1, 2016

You will have to qualify the terms of your question. I can make a guess, but I might be wrong.

#### Explanation:

In general, when we talk of solution concentration in percentages, we mean a percentage by mass, i.e.

"mass of solute"/"mass of solution"xx100% $=$ ??%. Thus $20 \cdot g$ of solute in $80 \cdot g$ of solvent (which is typically water) has a concentration of 20%(m/m). These can be converted to concentrations with units of $m o l \cdot {L}^{-} 1$ PROVIDED we have the density of the solution. Anyway, you will have to specify the terms of your concentration.