Types of Aqueous Solutions

at this point we know that solutions represent homogeneous mixtures. But what we need to realize is that there are different types of solutions that exist as well. Now we're going to say here that when solid salutes dissolve in a solvent such as water and equilibrium takes place, we're going to say here we have what's called a solution equilibrium. This is when the rate of dissolution and re crystallization of salutes are equal. Now dissolution. We know that means that are solid Saw you breaks up into ions. What crystallization will be the opposite of that. That's the process of where are dissolved. Saw you starts reforming back into a solid. Now there are three possible solutions that are created. There's a saturated and unsaturated or a supersaturated solution. Now here when we talk about equilibrium concentration, this is just the maximum amount of dissolve Saw you present in solution at a given temperature. So keep in mind we have solutions which are homogeneous mixtures and these solutions can either be saturated, unsaturated or super saturated.

Now here, we're going to talk about the different types of solutions. Now, the penalty amount of solute added to our solvent, our solutions can either be saturated, unsaturated or super saturated. Now, when we talk about the type of solution, we're going to say that our saturated solution is a stable solution as well as our unsaturated solution. The supersaturated solution itself though is unstable. Now the amount of dissolved solute in each. When we're talking about a saturated solution, that means we've reached our maximum amount of solute that's been dissolved for unsaturated. We say we haven't reached our maximum amount of potentially dissolved solute. So that means additional saw you can be dissolved. And then when it comes to our supersaturated solution we're gonna say super means greater than normal. So we've gone beyond our max, we've gone beyond our maximum amount of soil that can be dissolved. What effect does this have on our equilibrium concentration? Well here, if you're a saturated solution, we've reached our maximum amount of dissolved solute. So we've reached an equilibrium concentration. Now here, when your unsaturated, you can further dissolve more salute because you haven't reached your equilibrium amount. So you're less than the equilibrium concentration. And then finally for supersaturated, we've gone beyond our max. So that means we're gonna have more than our equilibrium concentration. Now, if we want to think about this in terms of visually, in terms of being added. So let's say we have 100 mls of water. This 100 miles of water can dissolve at Max 20 g of salt. So if I took those 20 g of salt, all of them would be dissolved. And here are water has changed into this purple solution to show that it's a saturated solution. Now again, we still have the 100 mls of water. Remember its maximum amount that it can dissolve is 20 g of salud. Here, we're not dissolving 20 g anymore. We're only dissolving 15 g. So it's not as purple as our saturated solution because there's still room to dissolve an additional five g of salute. And then finally here we have our super saturated solution Here. It can dissolve 20g max of solute unless I do things to force it to dissolve an additional amount here. One of the things that we can do is increase in the temperature by increasing the temperature. I can go beyond my 20 g of solute and in this case I'm successfully able to dissolve 23 g of solute. I've gone three g over my maximum, I am beyond my max amount of solute dissolved. And you can see as a result of this, the solution is even more purple because it's gone beyond its equilibrium concentration. Right? So, just remember a saturated and unsaturated solution are both stable. They happen normally, a supersaturated solution is not a stable solution. So it needs additional help adding heat is a good way of forcing a supersaturated solution to be formed. Right? So keep this in mind when comparing these three different types of solutions

here, we're told that the Saudi ability of a substance is 56 g per MLS of water at 20 degrees Celsius. So basically we can dissolve up to 56 g within 100 MLS of water at that temperature. Now he always saying a solution of this substance is prepared by dissolving 80 g in miles of water at 75°C. The solution is then slowly cooled, cooled slowly at 20°C without any solid forming. The solution is right, so were at a higher temperature, So he has been applied to it, allowing our solution to dissolve more than the 56 g that normally can hear. It's dissolving 80g. They're telling us that we're cooling it back down at a 20°C and nothing re crystallizes. That means we have still 80 g dissolved as we cool down to 20°C. So we're still dissolving more than our maximum amount, our maximum equilibrium amount. And because of that, because we've gone beyond our max, we are a supersaturated solution. So here We'd say, C is the correct answer. We've gone beyond our 56 g that we normally would dissolve at 20°C. Of course, it makes sense that we go beyond that 56° of that 56 g at a higher temperature. What's most important is when I get back down to 20°C. AM I still dissolving that extra amount? If I am, then I'm a supersaturated solution. So here options see would be the best answer. D doesn't work, because let's take it back down to 20°C and see if any re crystallization has occurred. That's when we know for sure we have a supersaturated solution here. These answers don't work either.