Find the volume percentage for a solution prepared from 15 grams of ethanol, and 100 millilitres of acetone. So, the first thing I want to do, is remind myself what a volume percentage looks like. Remember, that it means I have the volume of the solute, that's in millilitres over the volume of the solution, also in millilitres times 100, and I've gotta remember that the volume of the solution includes both the solute and the solvent. So I see I have the volume of the solvent, but I'm going to need the volume of the solute, which is the ethanol. Because it's the substance present in the smaller amount. So that's my solute. The acetone is my solvent. So now, I'm going to find the volume of the ethanol. So 15.0 grams, and I'm going to use the density, I'm going to put the 0.789 on the bottom, because I want those grams to cancel. And when I do this, I find that I get 19.0 millilitres of my ethanol. Notice, when I set this up, my grams cancel with my grams and I was left with units of milliliters. So now, I have the volume of my solute and the volume of the solvent. So now I can set up my calculation, and I get 19.0 milliliters over 100 plus 19.0 milliliters, times 100. And when I do the calculation, I end up with 16.0%. And we'll put a V over V just to indicate that this is by volume.