 Okay, so let's try this one. How many moles of HCl are in 20 milliliters of 12-molar Hd? Okay, so what do we know? We know the volume, but we need the volume in liters, okay? And we'll get to that in a second. Why? We know that one liter plus a milliliters cancels that amount. So we've got 0.0200 liters of HCl. And the polarity is 12.0 mole. Okay, that also means, remember, molar means moles per liter, okay? So we could also say 12.0 moles. We've got to remember the equation for molarity. Molarity equals the number of moles of solute divided by the volume of solvent in liters. So we've got that, the volume of solution, sorry, it's the volume of solution. We've got the volume of solution in liters, and we've got the molarity. So we're trying to calculate this variable there, the number of moles of solute. So we've got to isolate that variable. So in order to do that, we've got to get VL out of there. It's being divided there. So the inverse of division is multiplication. So when we multiply by both, VL by both sides, cancels out like that, okay? And we're left with the equation N equals VL times N. Does that make sense? So all we do now is plug in those numbers, okay? So VL is 0.0200 liters of the molarity. If you notice now, liters will cancel, okay? Times 0.02, 0.24, and we've got three state pigs, three state pigs, zero moles of HCl.