The Colligative Properties - Video Tutorials & Practice Problems

The Colligative Properties Concept 1

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

The Colligative Properties Example 1

You're Benzene, which has a formula of C686 has a boiling point of 80.1°C. What is a possible new boiling point? Once an unknown amount of glucose is added to the Benzene Solvent. So remember we discussed this earlier on, we say the more salute you add to a pure solvent than the higher the boiling point would be. So we're gonna say here we expect the boiling point to be a value that is now higher than 80.1°C. And if we look at all, our choice is the only one that's above this original temperature of 80.1°C is options. See We expect our temperature, which is reasonable to the 89.6°. None of the other ones make any sense. Boiling port would not stay the same and it definitely would not decrease adding salute to a pure solvent, increases your boiling point.

The Colligative Properties Concept 2

now the Van Hoff factor, which uses the variable I equals the number of ions produced from dissolving a soluble solvent. Now, when we talk about salutes, we group them as being either ionic or covalin in nature. Now remember ionic compounds are composed of a positive ion connected to a negative ion. That positive ion can be in the form of the ammonium ion or a metal and then that negative ion will be in the form of non metal. So here, if we take a look, we have sodium hydroxide, ammonium, carbonate and aluminum sulfate as our three ionic compounds, each one because their ionic can break up into ions here we have an A plus O H minus here it breaks up into two ions. We just said that the Van Hoff factor is a number of ions produced when a soluble solid dissolves. So since there's two ions, I equals two ammonium carbonate, breaks up into two ammonium ions plus one carbonate ion. For a total of three ions. So here I equals three Aluminium sulfate, breaks up into two aluminum ions and three sulfate ions. For a total of five ions. And because of that I equals five. Now Covalin compounds just compounds composed of only non metals together. Okay we're gonna stay here that they are because of this. They are non volatile. You're gonna say they are non I in Izabal or non electrolytes. Okay so here if they mentioned Covalin salutes, if they mentioned that they're non volatile, if they mentioned that they're non electrolytes we group them all under Covalin salutes. So here we have glucose, we have chlorine, we have methanol and here we have on something called Yuria. So um urine, that's one of the main components of it. All of these are co violent in nature and therefore they are non volatile. Which means they don't break up into ions and their non electrolytes, which also means they don't break up into ions because of that I equals one. Now technically zero ions are formed so they just stand the form that they're in so that still counts. They stay in the form that they're in so we just count them as one. So I for them with equal to one. So remember ionic compounds break up into ions. It's important you get the number correct to write. They'll find the right number for I for covalin salutes. They don't break up into ions there. I will always just be one in its value.

The Colligative Properties Example 2

which of the following compounds will have the largest value for the Van Hoff factor. All right. So for the first one we have aluminum chloride which is composed which is an ionic compound. So it breaks up into ions. It's composed of one aluminum ion and three chloride ions. So in total, that's four ion. So I equals four for the next one, it's Covalin because only non metals together. So I equals one for the next one it's ionic again causing is a metal, oxygen is a non metal. So it breaks up into zinc ion and oxide ion. That's two ions total. So I equals two. Next we have ammonia, which is NH three. It's Kovalev because only non metals. So I was one. Okay. And then we have P two S five which is also Covalin. It's only non metals together. So I equals one. We can see the one with the greatest Van Hoff factor value is A. I. Equals four for aluminum chloride. So here, the answer would be option a

The Colligative Properties Concept 3

So remember for the collective properties. The more salute you add, the more they can be affected boiling point and osmotic pressure will keep going up, freezing point vapor pressure would go down. Now the solid amount added equals the number of ions of that salute. Well remember that prevent a factor. So that's I times the concentration of that compound or salyut. Now this concentration could represent either molar itty or morality. And if for incorporating ions with polarity or morality then they become osmolarity and osmolarity. So remember osmolarity is ionic polarity. Oz morality is ionic morality. Right? So for osmolarity saw you formula we're gonna say osmolarity which is the amount of solute equals I the number of ions for the salute times the polarity of the compound as a whole as morality is the same kind of idea it equals I the number of salute on ions that we have times the morality of the compound. These two formulas will help us determine the amount of solute that a salute given to us represents, and that will help us determine which want to have the highest boiling point or which one has the lowest freezing point, etcetera. So keep this in mind. We use osmolarity and osmolarity to determine the amount of salt that is at.

The Colligative Properties Example 3

What is the ionic morality of potassium ions in 1.1, a mobile solution, potassium phosphate. All right. So, we want the ionic morality of potassium ions. All right. So we're gonna say ionic morality is just osmolarity. So here it will equal the ions of potassium ion times the morality of the compound. If we break this up, it breaks up into three potassium ions plus one phosphate ion. So how many potassium ions do we have? We have three. So that be three Times now, the morality of the entire compound is 1.8 mold. So three times 1.18 molo gives us the ionic morality of potassium ions. So that would give us option E As our correct answer. So it'll be 354 mol of potassium ions.

Which of the following compounds will have the highest boiling point?

• A. 0.10 M sucrose
• B. 0.10 M AgCl
• C. 0.25 M NH₄NO₃
• D. 0.45 M pure water

Which of the following compound will have the highest vapor pressure?

• A. 0.45 m dinitrogen pentoxide
• B. 0.10 m aluminum chloride
• C. 0.50 m iron (III) perchlorate
• D. 0.15 m calcium phosphate
• E. 0.30 m Potassium sulfide