 Okay. So let's try this one now. This one's number 8. I believe we got a number 8 on the practice test. Calculate the osmotic pressure of a 0.75 molar calcium chloride solution at 37 degrees Celsius. So the first thing you have to remember is that you need to calculate the osmolarity of this type of a problem. Okay? So you don't just calculate from the molarity. You have to know the osmolarity. And in order to do that, you need to know what calcium chloride is. Okay? So calcium, of course, is Ca and it's got a plus 2 charge, right? Chlorine has a minus 1 charge, right? So to combine those two and calcium chloride, it's going to be 1 calcium and 2 chlorines. And when you put that into water, you get this kind of. So the osmolarity just is a measurement of particles in solution. It's not a measurement of, like, concentration of calcium or concentration of chlorine. It's a measurement of the combined molecules. Okay? So in order to get the osmolarity, you need to take the molarity of calcium chloride. So the osmolarity of particles will equal calcium chloride, 3 particles, molar particles. There's some molar calcium chloride. Molar calcium chloride cancels and we just get 0.75 times 3.25 osmolar or molar in particles. Where do you get those 3 particles? Because there's 1 plus 2, 3 actants. There's 3 particles. So that's the concentration you're going to use for the subsequent equation, which is the equation for osmolar pressure. Osmolar pressure is pi times the osmolarity times currently is in degrees Celsius, 37 plus 273 to get Kelvin is 310, pardon me, moles per liter, and then R is going to be 0.0821 liter ATM over 1 mole Kelvin. Multiply that by the temperature, which is 310 Kelvin. So moles cancel, liters cancel, Kelvin's cancel, and you're left with ATM, which is good because it's a pressure and that's the pressure unit. So you go to 2.25 times 0.0821 or you cancel. And your osmotic pressure is 57.18.