 Okay, we're just going to go over one quick tip for dealing with percent or molar solutions just in how you think about them and how you set them up. So you're going to want to define your concentration in terms of 100 mLs for a percent solution and in terms of one liter for a molar solution. So and that's just to help you because we know that a percent is out of a hundred. So if we set it up so that 100 mLs is our base, we can much more easily translate from a percent and it'll help us set up our proportions. So likewise, if you're dealing with molarity you want to use a liter because moles per liter is how molarity is defined. So let's just go through a quick example to show you how this will help. So if you're asked to prepare 25 mLs of a 4% weight to volume solution of sucrose, you want to set up your concentration this 4% in terms of 100 mLs. So you'll have 100 mLs and you'll have that 4% equals 4 grams out of 100 mLs. So that helps you start with your proportion. We know we need a 25 milliliter solution that we're ending with. We're going to multiply both sides by 25 mLs. You can simplify that so that it's 4 grams over 4 equals x. x is equal to 1 gram. So then you would dissolve 1 gram sucrose and bring to volume 25 mLs to prepare this solution. So this just helps you with setting up your proportions. If you always think of a percent solution as out of 100 mLs, then it works the same way with a molar solution. Just do a quick one with a molar solution. We want to do 200 mLs of a 3 molar sodium hydroxide which has a molecular weight equal to 40.0 grams per mole. We know that our 3 molar equals 3 moles per 1 liter. That's where we're setting up our concentration in terms of 1 liter. And so we know that, and here I'm just going to say 3 moles per 1000 mLs because we know we want to end up with 200 mLs. We know that there are 1000 milliliters in 1 liter. So we're going to know that that equals x out of 200 mLs. So we're going to multiply both sides by 200 mLs. This should be a thousand, not just 100. That's why it wasn't working out in my head. So this is going to be 0.6 moles is how many moles we need to add. And then we just know that 40 grams per mole equals how many grams out of 0.6 moles. So we can solve that for x, we'll get 24 grams. And so again, here we're dissolving 24 grams and we're going to bring to a volume of 200 mLs. So you can see how setting up your proportions becomes easier if you can move your concentration into terms of a liter if you're dealing with molarity and into terms of 100 mLs if you're dealing with percent.