Mass or weight percent is the percentage of a given element or compound within a solution. Now, we're going to say that mass percent can be seen as the mass component, which is usually the mass of our solute divided by the total mass of our solution times 100. For example, if we're given 23% NaOH, this means that we have 23%, which translates to 23 grams of NaOH over 100 grams of solution. Because we're dealing with the percentage, we always assume it's out of 100 grams.

We can further expand on this and say that we have 23 grams of NaOH still on top and remember, a solution is made up of solute plus solvent. So, that'd be 23 grams still of NaOH plus 100 minus 23, which gives us 77. 77 grams of our solvent. Within our calculations, it's important that you are able to see that mass percent can be broken down like this, and it can further be expanded where we look at both the solute and solvent components individually.

Keep this in mind as we approach more questions dealing with mass percent. Now, look at example 1. Take a look at it. Once you do, attempt it on your own. If you get stuck, move on to the next video and see how I approach example 1.