General Chemistry

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4. BONUS: Lab Techniques and Procedures

Filtration and Evaporation

FIltration and evaporation allow for the separation of a solid from a liquid mixture. 

Filtration vs Evaporation

Filtration and Evaporation

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everyone is on the first part of this video. Let's talk about filtration. Now, filtration is just the process of separating out a solid from a liquid. So here we're going to say the technique involves the separation of an insoluble solid from a liquid by its moving through a filter. So we're gonna be using filter paper in terms of filtration. Now, here we're going to say that the insoluble solid is left behind on the filter paper and it's termed the residue. So the solid that you get at the end stuck onto the filter paper is called your residue. And the southern passes through the filter paper is tall is termed the fill trade. So here we have two examples of filtration. Both of them deal with using an air Lemire flask. So both of them have this flask involved. And the first one, we're using a simple Lemire flask and we're going to use a funnel within this funnel. We have our filter paper that has been folded in order to fit properly within this funnel. This filter paper kind of serves as a semi permeable membrane. It allows the passage of our solvent or fill trait through and then the solid actually can't pass through and it's stuck on the residue paper on the uh filter paper. So the residue will hear itself to this. Now this method is a little bit time consuming. It takes a good amount of time. It works best if you're solid is really not that dissolved within your solution. Now, the second type of filtration we can have here involves a different type of flask here, it has a vacuum pump that can be attached to it. This vacuum pump can help rush the fill trait faster to the filter paper. We're using a Buckner funnel. And of course, we still have our filter paper here. Where are solid can adhere to it. Now the vacuum pumps gonna pull on basically cause a vacuum within our flats, which will draw out the filtration faster. Now this is best used if you want want to do this process faster. And also it works best if your solid is more partially dissolved because by using the vacuum pump, it's actually going to decrease the temperature around the Buckner funnel. This drop in temperature will help to re crystallize they're already more dissolved solids. So both of these options are different types of filtration is that you can use. The first would be much simpler, requiring a few more parts to it. Now, a great example of everyday use of filtration involves a coffee filter. So when you put a coffee filter within your coffee machine, what does it do? It allows the coffee bean grinds or residues to remain behind on the coffee filter. And in the filter rate, which in this case is your coffee filters through. Now that we've talked about filtration. Let's look at evaporation. So evaporation sometimes called crystallization. This is the technique involved the separation of a soluble solid from a liquid based on the boiling point of the solvent. So here this is different and the other ones we had insoluble solids or solids that were a little bit more soluble here, it's completely soluble. And here we have a Bunsen burner and what we have here this bowl. This is our evaporation bowl or heating bowl. And basically, if we heat this up enough, we'll be able to evaporate or vaporizes the liquid portion and what will be left behind at the end are pieces of solid material. So both of these techniques, filtration and evaporation are just useful ways in which we can separate our liquid from our solid within a given mixture.