Now the four collective properties discuss what happens to a pure solvent as a salute is added to it. So they're discussing what happens as our pure solvent transitions into a solution. Because remember when we add salute to a solvent, it becomes a solution, we're going to say as salute is added to a solvent. Some cognitive properties will increase while others will decrease. Now here, when we take a look at boiling point and osmotic pressure, we're gonna say that these two collective properties will increase the more salt we add to our solvent. Conversely, we're gonna say that are freezing point of vapor pressure. The more sought to add to my solvent. The lower they go, okay, so just remember these are the two effects of adding salute to a pure solvent. Now, let's discuss these four collective properties a little bit more closely. So boiling point. Remember boiling point is just the temperature where we're going to have an equilibrium between our liquid and gas phases. Alright, so remember we have our liquid becoming a gas or vaporization and then we have our gas condensing down back into our liquid boiling point. Is when there's an equilibrium between these two changes, freezing point freezing point is where there is an equilibrium between our solid phase and our liquid phase. So, going from solid to liquid, we have melting or fusion occurring and then going from liquid to solid. We have freezing occurring freezing point is when both of these phase change properties or processes are happening at the same time. So they're at equilibrium with one another. Now vapor pressure, we're gonna say here, that vapor pressure is basically the pressure exerted by a gas at the surface of a liquid. We're gonna say this is measurable also, again, the whole idea of being an equilibrium. Finally, we have osmotic pressure. Osmotic pressure is just the force that drives osmosis. Remember the movement of water from an area of low concentration to an area of high concentration. So here we have an illustration where this side is more concentrated and so water would rush towards this side here. What is this? What effect does this have? Well, the right side, the water level be lower and the left side the water has increased because again, water moved from an area of low concentration to an area of high concentration. Right? So we'll go a little bit more in detail in terms of the mathematical applications of each of these collective properties, but for now, realize that they have to do with our transition from a pure solvent to a solution through the addition of some type of salyut