zolyblog.info: Matter: Solutions
A range of solutes, including sucrose, trehalose and sorbitol are accumulated by .. In this case, however, the ratio of solvent molecules to solute molecules is high, and so We thank Peter Rand for advice on sample preparation. .. Comparative Analysis of Water Relationships at the Organismic, Cellular and Molecular. That works! In most chemistry (but not nuclear reactions!), mass is always conserved, so. m solution = m solvent + m solutes. Mass is also equal to density times. but also on the solvents in which the solutes are dissolved. In this paper, relationships between solvent shifts for the hydrogen atoms in cycloalkanes and those in n-alkanes are discussed in connection with the loca- . for helpful advice.
So that's what homogenized means. So a homogeneous mixture is the same thing: Now, that is further divided, depending on how large the particles that are diluted in the mixture are. So if we have a situation where the particles are larger than nanometers-- and that might sound large, but it still isn't that big, because a nanometer is one-billionth of a meter.
But if we have particles mixed in, say, water-- but it doesn't have to be mixed in a fluid, or especially it doesn't have to be water-- that are greater than nanometers, we're dealing with a suspension. And the one characteristic that people associate with a suspension is that whatever you suspend in it, whatever you mix in-- let's say I have a suspension here. Maybe it's water, just because it's easy for me to visualize. And I have some big particles here-- that they'll stay in the water for some amount of time, but eventually they'll deposit on the bottom of the container.
Or sometimes, they'll actually float to the top. Depending on whether they're heavier or depending on their buoyancy, they'll either float to the top or the bottom. In order to get it back into the suspension state, you've got to shake the bottle. So two examples I can think of this.
One is mixed paint, right? Before you paint your walls, you've got to make sure that the can is well shaken. Otherwise, you're going to get an inconsistent coat. The other, that's close to my heart, is chocolate milk. Because when you mix it up, it's nice and it seems homogeneous, right?
Relationship between solute, solvent, and solution?
And I already have milk here. So right at first when you stir it nice, you have all the little chocolate clumps in there, at least the chocolate when I make it is like that. But then if you let it sit around for a long time, eventually all the chocolate is going to collect at the bottom of the glass.
Actually, different parts of it. I've seen situations where the sugar all collects at the bottom and then you have these little clumps at the top. But you get the idea, that the mixture separates. And that's because the particles in either the paint or the chocolate milk are greater than nanometers. Now, if we get to a range that's a little bit smaller than that, if we get to the situation where we're at 2 to nanometers, we're dealing with a colloid.
That word, I remember in seventh grade, I think you learned it in science class: And a friend and I, we thought it was a more appropriate word for some type of gastrointestinal problem.
Relationship between solute, solvent, and solution? | Yahoo Answers
But it's not a gastrointestinal problem. It's a type of homogeneous mixture. And it's a homogeneous mixture where the particles are small enough that they stay suspended. So maybe they could call it a better suspension or a permanent suspension. So here the molecules are-- so let's say that's my mixture. So water, maybe it's water. It doesn't have to be water.
It could be air or whatever. Now the molecules are small enough that they stay suspended. So the forces, either their buoyancy or the force-- actually, more important, the forces between the particles and the intermolecular forces kind of outweigh these particles' tendencies to want to exit the solution in either direction.
And so common examples of these-- well, the one I always think of, for me, the colloid is Jell-O. Jell-O is the brand name, but gelatin is a colloid. The gelatin molecules stay suspended in the-- the gelatin powder stays suspended in the water that you add to it, and you can leave it in the fridge forever and it just won't ever deposit out of it.
Fog, you have water molecules inside of an air mixture. And then you have smoke. Fog and smoke, these are examples of aerosols. This is an aerosol where you have a liquid in the air. This is an aerosol where you have a solid in the air. Smoke just comes from little dark particles that are floating around in the air, and they'll never come out of the air. They're small enough that they'll always just float around with the air.
Now, if you get below 2 nanometers-- maybe I should eliminate my homogenized milk. If you get below 2 nanometers-- I'm trying to draw in black. If you're less than 2 nanometers, you're now in the realm of the solution. And although this is very interesting in the everyday world, a lot of things that we-- and this is a fun thing to think about in your house, or when you encounter things, is this a suspension?
Well, first, you should just think is it homogeneous? And then think is it a suspension? Is it eventually going to not be in the state it's in and then I'll have to shake it? Is it a colloid where it will stay in this kind of nice, thick state in the case of Jell-O or fog or smoke where it will really just stay in the state that it's already in? Or is it a solution?
And solution is probably the most important in chemistry. And in general, it's an aqueous solution, when you stick something in water. So sometimes you'll see something like this. You'll see some compound x in a reaction and right next to it they'll write this aq. They mean that x is dissolved in water. It's a solute with water as the solvent. So actually, let me put that terminology here, just because I used it just now.
So you have a solute. This is the thing that's usually whatever you have a smaller amount of, so thing dissolved. And then you have the solvent. This is often water or it's the thing that's in larger quantity. Or you can think of it as the thing that's all around or the thing that's doing the dissolving.
I've got 6 out of 8 molecules that are green. So what is the new partial pressure looking like?
Well, 6 out of 8 means that the percentage is going to be different. So I've got a new number here and here. This is my new partial pressure. And the reason I actually went through that is because I wanted to show you a way of thinking about partial pressure, which is that if the number of molecules in a group of molecules-- if the proportion goes up-- then really that's another way of saying the partial pressure has gone up. And if you have more molecules, what does that mean exactly?
Well, from this person's standpoint, this person that's watching this surface layer, they're going to see, of course, molecules going every which way. Every once in a while, these green molecules are going to go down and into the liquid. They're going to bounce in different ways, and just by random chance, a couple of these green molecules might end up down here in the surface layer.
So that's something that you would observe. And you'd probably observe it more often if you actually have more green molecules. In other words, having a higher partial pressure will cause more of the molecules to actually switch from the gas part of this cup into the liquid part of the cup. So I don't want to be too redundant, but I want to point out that as the partial pressure rises, we're going to have more molecules, more green molecules, going into the liquid.
So now let me actually ask you to try to focus on this little green molecule, this little fella right here, this guy. Now imagine, he's just entered our world of H2O's, and he's trying to figure out what to do next. And one thing he might do is pop right back out.
You'd agree that that's something he could do, right? If he entered the liquid phase, he could also just re-enter the gas phase. And a lot of molecules want to do that. They want to actually get out of the liquid because the liquid is a little stifling.
It's kind of crammed in there, a lot of H2O molecules around in this case may not like that. So it turns out you can actually look up, in a table, this value called K with a little h. And this H with a little h is just a constant.
Suspensions, colloids and solutions
So this is just a constant value that's listed on a table somewhere. And this K sub h actually is going to take into account things like which solute are we talking about.
When I say solute, you basically can think of these green molecules. So which is it? Is it a green molecule or a purple one or a blue one? What exact solute are we talking about? And what solvent are we talking about? Are we talking about water? Or is it dish soap or ethanol or some other liquid that we're worried about in this case?
And finally, what temperature are we talking about? Because we know that molecules are going to want to leave. Especially molecules that prefer to be in a gas phase, they're going to want to leave the liquid, and they're going to do it much, much more if the temperature is high.
Because when the temperature is high, remember, the little H2O molecules are dancing around and shaking around, And that allows them to free up and leave. So these are three important issues. What is the solute? What is the solvent? And what is the temperature?
And if you know these three things, you can actually-- like I said, you could look up in a table what the Kh is. And that tells you a little bit about that red arrow. What is the likelihood of leaving the surface layer? So just as before, where we talked about going into a liquid, this is now going out of liquid.
So Kh, these values that I said you can find in a table, tell you about the likelihood of going out of a liquid. And the partial pressure tells you the likelihood of going into a liquid.