Hello and welcome back to another video
with ItsDrDan and today we're going to be learning about solubility trends. Now when it comes to a solubility trend,
this is all about how you can label solutions based on how concentrated
they are, meaning how much of a solute exists within the solution. So because of that, you can label
them as saturated, unsaturated, or super saturated solutions. And this is what I'd like to describe
as the Goldilocks issue when it comes to solutions, meaning that it's
very
similar to that old nursery rhyme all about Goldilocks and the three
bears where she was trying all the different types of porridge that was
too hot, too cold, and just right. Well, it's very similar to that here as
well, where we have two concentrated, not concentrated enough and just right
is how we are going to be looking at concentrated solutions as well and how
that affects the chemistry behind them. So we're going to take a look at
this and look at the different types. We're going to
learn how to read
the charts for how you can actually determine what type it is as well. And we'll go through many different
examples and demonstrations to help show you what these all look like. Alright, let's go take a look, and thank
you so much for stopping by, and let's go look at the next, next, uh, example. Solubility in the Goldilocks issue. So this is all about
describing how solutions work. If you remember, a solution is composed
of both a solute and the solvent. The solute was the min
or part,
which is dissolved by the solvent, which is the major component. Alright. Now, depending on how much solute you
have, so in a way of like, how is it too sweet or is it too salty, right? When you're thinking of trying to
dissolve these different things will help you actually describe saturation. So the three types of saturation are all
about how much of a solute there are. I like to think of it in terms of if
you were to ever make, let's say, uh, iced tea at home or maybe coffee, for
exa
mple, and if you make iced tea and you are added, let's say, add sugar to
it, well, you taste it and you might be like, oh, it's not quite sweet enough. That's an unsaturated solution, meaning
that the solution is holding less than its maximum amount of solute. Meaning you can add more. It's possible to add more. So now it's all about what is the limit
that water can dissolve that solute. Because you can remember water
molecules are surrounding the ions here. So there's only so many water molecu
les
available to surround all these molecules. This is, there's more to be
dissolved is what unsaturated means. Saturated is when you reach the maximum
threshold for the solute to be dissolved. So that's saturated. So that is like, unsaturated
is like, not sweet enough. Saturated is just right. This is like, okay, the
Goldilocks situation. This is right where you want it to be. You don't want it to
go any more, any less. It tastes perfect the way it is. Now super saturated is when it goes
way be
yond what it's able to handle. So that means that you are way above
the maximum and it's still in solution. Somehow this one has like the super
strength that's available to 'em. We'll show you how that's
exactly possible, right? How can you go above, right? Because usually when you're saturated,
if you add a more solid into it, it's just gonna precipitate out. But there's a way to kind of trick the
molecules into being super saturated. So this is all about not
concentrate, not concentrating, bei
ng, being all the way at the top. So not concentrate enough concentrated
and way too concentrated is the bottom. So let's look at this a little
bit further and be dissolved. You can add more. So by adding solute, it will dissolve. So it means it's not that
quite not sweet enough for you. You want to add a little
bit more sugar to your tea. You can do that. Saturated means that no more
can be dissolved, right? It's at its maximum. It's like, oh, this is just right. I don't want anymore. Because a
nymore would be like, too gross. You'll have that. Oh, it's too, too sweet. Meaning, and if you add more to it,
then it'll start precipitating out. It will not dissolve. Supersaturated means that somehow you
manipulated the science behind it. And there's already too much dissolved. But how is that possible? Well, this is unstable. This is all about trying to manipulate
the temperatures to make this possible. So we're going to talk about
the temperature trends and how that plays a role as well. B
ut let's take a look at what super
saturated is all about being that I have a demo for you to show this
with a super saturated solution. What this is all about is
when you heat up a solution. And you dissolve as much solid in it
as possible, essentially what's going to happen is more can be absorbed. So if you cool the solution down,
technically all of that that was dissolved can't fit in there technically. So how can you, how can
that actually exist? Well, right now it's in a state where it's
i
n an equilibrium, but it's very fragile. It's very unstable. So all it takes is essentially one little
crystal to be added to this solution. So what you see on the edge of
the spatula here, the scupula, is one little tiny crystal. And we're going to add it here
into the volumetric flask. And what you are going to see
is it's going to precipitate. Notice how it looks like snow
forming and ice is forming. All that precipitates out and it's
expanding, expanding, expanding because there's too much i
nside solution. It's no longer stable. Therefore, it crystallizes
completely and solidifies. It went from a liquid to a solid
instantaneously because there was too much in the solution. So now it's a solid and fully
precipitated and that is supersaturation. That's when you have this
special scenario just like this. All right, so how can you tell
which version is it going to be? Well, the idea here is in order for us
to tell is it going to be saturated, unsaturated, or supersaturated is you
need
to be able to read solubility tables. So, what a solubility table is,
it's all based on temperature. So they look a little bit like this,
where we have all these different curves that are labeled for the different
substances that we have available to us. Now it's all about how water dissolves
these salts into their electrolytes. So every single one of them is
different, like you can see salt is relatively a straight line. You see sodium phosphate is going up. You see KNO3 is going straight up. G
lucose is like here, and all of them
have their own unique trend to them. Well, now when we're reading this,
you can see the x axis is temperature. The y axis is solubility, meaning how
many grams of your solute can dissolve for every 100 grams of solvent. So there's a limit that's available. So if we were to read this, we
can label what a solution is. So let's say I wanted
to do it for glucose. How could I label it? Well, let's take a look. So glucose is right here
is the line for glucose. And
what we are going to
do is look at 40 degrees. And we see that it goes
to right about here. So the way that we would trace that across
is we see that at 40 degrees, uh, we will have a solution that's right around 125,
130, which, so what does that tell you? That at 130 grams of glucose at
40 degrees, that's saturated. So let's kind of mark that
spot for ourselves here. So here we'll do that
in a different color. So this is where the saturation
limit is for 40 degrees. Okay, so let's kind of conn
ect that. All right. So we'll write that as, uh, we have
around 130 grams is saturation. Now, what would be considered unsaturated? So if we were to label that in
blue, everything below here would be considered the unsaturated limit. So everything that's lower
than 130 grams of solute. And now when would it be super saturated? Well, that will do it when you have
anything above this purple point. will be considered to be super saturated. So we're going to label this part of it,
and it's going to
be anything greater than 130 grams of your glucose value. Now it's going to be a little bit
easier than that typically when you're trying to read these and use them,
but it's all about trying to pinpoint exactly where you're at on the graph. So let's take a look at some
more examples and try to understand this a little bit more. Assume we have dissolved the following
amounts of solute in 100 grams of water. Label them as unsaturated,
saturated, or supersaturated. Okay so the first one, 40 grams
of
sodium chloride at 100 degrees C. So what we're going to look at is we
see here's 100, here's 100 degrees C right at the corner of the screen. And we are going to take that
all the way to NaCl which is this yellow curve at the bottom. So, where we're going to go is
to 40 grams, and what you can see is those two points are meeting
the yellow line that's here. So what that's going to tell you is that
this is the saturation limit for NaCl. So NaCl is going to be saturated,
being that it is match
ing that limit. Let's try the next one. It says 18 grams of NaCl at 60 degrees C. So first we gotta find sodium phosphate. That's the line that's right here in blue. So it's 60 degrees. That will go right to
about here on the curve. And what it says is 18 grams. So 18 grams is right down here,
technically, on the y axis. So it's well below where
we're currently at. So what that means is unsaturated. that you can add more. In fact, you can go up to about
50 grams of sodium phosphate before it bec
ame saturated. The next one is sodium nitrate. So it says 100 grams of sodium
nitrate at 10 degrees C. So here's sodium nitrate
is this blue curve here. So we are at 10 degrees C. So 10 degrees will trace up to our line. So right around here, And what we
see is that, okay, at about roughly about 80 grams is how much can
fit in solution at 10 degrees C. So what this would technically be is
a super saturated solution because it is above where it needs to be. So you can kind of see like here's wher
e
100 is, and it's going like down to here where it would be the saturation limit. All right, so now another thing to
kind of tell from these graphs as well is that solid solubility notice
how all of them are increasing as they go up in temperature. So as we go up, we're going kind
of in this general direction here. Okay. We see it's increasing, right? And all of them are sloped
upwards as a result. So most solids are generally more soluble. The higher temperature. One way to think of that too i
s if you
have like iced coffee or hot coffee or hot tea and iced tea is if you try to
add sugar to any of the ice products, typically it doesn't dissolve very well. It takes a while for it to dissolve
and it has to do with this. So usually they'll have like
liquid sugar or liquid syrups and things like that to add. Because they're a little
bit easier to dissolve. Now let's take a look at the next concept. So going back to that example I
showed earlier about super saturation, well, super saturati
on is a result of
temperature change is what I mentioned. So let's say if we had sodium
phosphate, for example. And I were to put ahead of that at
80 degrees C, so that's right around, uh, right around this point here. So if I were to cool that down, let's
say I put the maximum allowed at 80 degrees, which would be roughly
about, maybe about 70, 75 grams or so. So now if I cool that down to, let's say,
20 degrees down to here, Well, technically the solubility limit's only 10. Well, what does tha
t mean about
all those grams that are already in solution if I put all of them in? Well, they're still going to be in
solution until you add a leather crystal, so it's all about cooling it down. So typically if you want to put more in
solution, you have to cool it back down. So let's say if I put that 75
grams in the 80 degrees, this should be referred to as saturated. Now if the 75 grams is still in
there, this is now super saturated because of the temperature. Being that essentially the
satura
tion limit around 20 degrees would be roughly around maybe 10
grams or so, would be saturated. So it's all about labeling depending on
where you add on the temperature scale. So let's take a look at our last
example all about saturation, how we label it based on temperature. The last part is all about gases. Well, we've been talking about solutions
a lot and we have and have posted a ton of videos on gases lately. So what about gases in water? Do they dissolve as well? Well, of course they do, r
ight? So if you think of, uh, if you have a
soda and it has carbonation in it, or how do fish essentially live, right? They actually breathe oxygen too through
oxygen that's dissolved in water. Well, gases do dissolve, but the thing
about them is that their solubility is really quite different than, than solids. So on the left hand side, I have
the trends here for nitrogen oxide, oxygen, carbon monoxide, methane. And one thing you'll notice is
that the slope is the opposite. They're actually all
going downwards
when temperature increases, meaning the hotter it gets, the more difficult
it is for them to be able to dissolve. So now what exactly, why,
what is that all about? Well, one thing about is being that
that decreases as temperature increases. It's all about thinking of
kinetic molecular theory. Gases behave like billiard balls,
they bounce all over the place. And the more kinetic energy they have, the
higher the temperature, the more they're going to actually bounce as a result. O
ne way to think of it as an analogy
is imagine giving like a five year old about 10 pounds of candy, right? They're going to be
running around like crazy. Well, the higher the temperature
goes, the more those gas molecules are going to move. And they're going to continue
to kind of bounce around like a little ping pong ball, like going
all over the place as a result. So, the more, the hotter it gets,
the more of a problem that is. Now, in terms of a bigger
effect, that could have a huge, even gl
obal effect as well. Global warming is one of the big
issues that we're always bringing up in the scientific community. The hotter the earth gets, the more,
the less oxygen that's actually going to be dissolved inside of water. So, in terms of aqua, uh, marine
wildlife that relies on oxygen to live. The hotter and hotter it gets, the
less oxygen there is, meaning the less fish or even the smaller size
that they will be when they grow. It can be a really big issue. So let's take a look at some ot
her
things as well when it comes to this too. The other part has to do
with not only temperature of gases, but the pressure too. So gases are, they're always
under pressure all the time, just like students and ourselves. So the solubility of a great
gas increases with pressure. I know this didn't quite fit
anywhere else, but I wanted to make sure we talked about it. So I drew some cans of cola
here to kind of try to emphasize exactly what this is all about. So let's say if you have a soda can or
soda bottle, and if you're not opening it, one thing that's really inside of that
mall inside of there is there is if you were to zoom in on the, on the molecular
level, you will see that there's going to be CO2 dissolved within the solution. And that's because there's so much CO2 in
the, in the space above it, That's going to be pushing all the gases into solution. Now, when all of a sudden you open up
the can and it goes, when it opens, right, that standard sound that you've
heard all heard b
efore, all the CO2 is going to escape because it's going
from an area of a really small volume. to the open space, a big volume. Now, when that happens, well, all
the gas molecules that are bouncing around, they, now, there's not
going to be so many of them to try to keep, uh, CO2 in the liquid. Therefore, your soda is
going to go flat over time. So one thing to kind of keep in
mind is, well, how do you keep preserved soda for a really long time? Well, one is don't open it as many
times if it's
a two liter bottle. And if you're going to probably drink it,
you know, try to probably drink as much of it in one sitting as possible because
the more times you open it, the more the gas is going to have to fill up the entire
space again to equilibrate once more. All right, that's all I have on solutions
in terms of how to label them and how to learn how we're learning all about them. Until next time. Thank you all so much for listening. And if it's your first time here, please
hit that like an
d subscribe button and please comment below if you have any
questions, I would love to answer them. All right. I hope you all have a wonderful
day and I'll see you all later. Bye now.
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