Now, in order to separate the different components of a mixture, it first must be heterogeneous. So we need them to be in different phases from one another. Now, in this form, each component maintains its individual physical properties. Now, chemical reactions rarely produce a single pure product, so these types of mixtures are common.
Now with distillation, we're going to have two different apparatuses that we can use for distillation. We're going to say this technique involves a separation of liquids and our gases based on a difference in their boiling points. There are many types of distillation methods, but the two most common forms are simple and fractional distillation. So from these two images, the one on the left represents a simple distillation and the one on the right represents a fractional distillation.
Now they have some things in common with one another, but they also have some differences. We're going to say they both have thermometers here which help to monitor the temperature because we're trying to figure out differences in boiling point. And let's say that both of them have a mixture of few compounds, one compound and one compound B, and both of them have a heating source here. This one's using a Bunsen burner, this one here is using a hot plate. They both serve the same function to heat U, our mixture.
And what we're going to say here is that for the simple distillation and for the fractional, let's say that compound A is methanol. Methanol is an alcohol with a boiling point equal to 67°C. Compound B, Let's make it water, which we know it's boiling point is 100°C. Both of these sources are going to heat up my mixture. What's going to start happening is they're going to vaporize and become a gas and they're going to travel up here and up here.
In the fractional distillation, we have here what's called a fractional column. We don't have that with simple distillation. In this fractional column we have little beads. These little beads are supposed to help us to have more surface area for the gas particles to travel to. This also serves another purpose because it helps to lengthen the amount of time it takes for the gas molecules to get through the column. In doing that there, some of them are going to recondense back into a liquid. This helps us to increase the cycles of vaporization and condensation. Fractional distillation is a longer process.
What happens now is some of the gas particles will travel here and travel here, and they're going to get to these two tubes. Both of them are called live big condensers. Basically they're both connected to hoses. This hose here is cold water that's going into the tube and filling it up here, and this one helps the cold water to exit. You have warmed gas traveling through this tube, traveling through this tube and on either side we have cold water. This is going to help it to condense and so it's going to drip down as liquid here.
What simple distillation. It's faster and you make a bigger yield of this filtrate here. Unfortunately, it is not as pure you're going to get. Let's say you wanted to isolate ethanol. Ethanol will vaporize sooner because it has a lower boiling point. You're trying to isolate ethanol, but you're going to have a mixture of ethanol and water here. With fractional distillation, the process is longer because it has to travel through the fractional column which has those beads. But you're going to get a much better pure product at the end here. It's going to be a majority of A. Most of the water is going to recondense back down, drip into here, get vaporized again. You're going to have more cycles of condensation and vaporization.
Now simple distillation is great if you're 2 substances have boiling point differences greater than 25°C. So in this example where I use methanol and water, their difference in temperatures 33°C. So simple distillation here will be good. But let's say that we changed compound A from methanol to ethanol. If I change it to that, it's boiling point is now 97°C. Those temperatures are too close, so simple distillation will not work. You will need to use fractional distillation. Fractional distillation works better if the boiling point difference between your two liquids is less than 25°C. Here the process is longer. You don't make as much of this filtrate liquid, but it's going to be very pure. It's going to be more of ethanol or methanol.
Now here, if we take a look at this graph, let's say here that we have temperature and we can have it in degrees Celsius or Kelvin U to you and it's increasing as we go up. And let's say we're going back to our original methanol water mix. So here we have mole fraction of methanol and here we have mole fraction of water O. Here let's say we start out with zero amount of methanol and here we have just all water. Overtime our amount of methanol would increase. So point 20.40, point 60.80, and then here 100% methanol and here's 0.20.40.60 and then .80.
So we're starting out here and let's say we're starting out with a sample that is a lot of methanol or I mean a lot of water initially. As we start to vaporize our mixture, we're trying to get to the point where we have 100% of the filtrate we want, which in this case is ethanol. Each one of these levels represents A vaporization that occurred. Vaporization. Vaporization 1-2 and three. Because I told you through the through the glass beads are in the fractional column, the gases travel. It takes so long that some of it reconnects back into water at the bottom where it's vaporized again and go through the whole process. We're going to have more instances of vaporization and condensation, which causes more cycles of vaporization to happen with the hope of when you get to your filtrate at the end, it's going to be 100% methanol and 0% of water. And what you have back in the original container that's still on the hot plate is just water.
So this is what this is showing us. It's showing us a vaporization condensation cycle that's occurring within fractional distillation. So just remember if you're trying to make it quick and try to get the 2 sample separated and the temperatures are greater than 25°C terms of boiling point, you can go with simple distillation. But if you want a pure filtrate at the end, fractional distillation is the better option.
