 OK. So let's try this one. It says, what would be the volume of hydrogen gas that was produced from hydrochloric acid reacting with 0.165 grams of aluminum metal according to the reaction equation picture? So we're looking for volume of hydrogen gas. And we've started out with the mass of aluminum. So what's the first step we need to do? The first aluminum to moles. That's the first step. This is a balanced reaction equation, so we don't have to balance that. That would be the first step first. So what would we put at the bottom here? Well, what is it? 26.98 grams of aluminum. And at the top? One mole of aluminum. So watch. Cancel, cancel. So we're at moles of aluminum. That's not volume of hydrogen, right? So we've got to keep going. So what are we going to do now? Molar ratio. The molar ratio. What ratio are we going to use? Hydrogen. How many moles of hydrogen? Three moles. Three moles of hydrogen. And down here? Two moles of aluminum. Two moles of aluminum. Volume of hydrogen. Well, I have to give you that conversion factor in order to continue along, right? So one mole of any gas is 22.4 liters of gas. So one mole of hydrogen is 22.4 liters of hydrogen. So what am I going to put on the bottom down here? One mole of hydrogen. And up here? 22.4 liters of hydrogen. 22.4 liters. Are we at volume of hydrogen now? Yes. OK, so we can just solve now. Remember how I taught you to solve, OK? Plug it in and make sure we get the same answer. 0.165 times 3 is 22.4 divided by 26.98 divided by 2. And since they wanted it in liters, we're going to get 0.205 liters of hydrogen gas. Did we get that together? Yes. OK, wonderful. Wonderful, wonderful, wonderful. Any questions on that one? A little more detail, but.