in today's video we're going to look at how we can separate both soluble and insoluble solids from liquids using techniques such as filtration evaporation and crystallization before we start though i just want to point out some terminology if we place a solid in a liquid and it doesn't dissolve like if we put some sand in some water then what we have is a mixture between a liquid and an insoluble solid on the other hand if we have a liquid and a soluble solid so where the solids does dissolve like if we put some sodium chloride salt in water then what we have is called a solution with the sodium chloride being the solute and the water referred to as a solvent the first and simplest technique that we're going to look at is filtration which separates insoluble solids from liquids this is basically the same process as using a sieve to separate food when you're cooking but in chemistry we normally use filter paper which has lots of tiny holes in it that are small enough so that water can pass through but not solids we often place the filter paper within a filter funnel as well so that we can easily pour our mixture through it leaving the solid behind on the paper however if we instead have a soluble solid in our liquid and it's actually dissolved then we have a solution and this time we won't be able to filter it out so here we have two options for separating a soluble solid from a liquid evaporation or crystallization for evaporation we place our solution in an evaporating dish or a crucible which we normally place on a tripod and then slowly heat it with a bunsen burner this will cause a solvent to start evaporating and the remaining solution to get more concentrated after a while crystals will start to fall because it's so concentrated and eventually all of the solvent will disappear leaving us with dry crystals of our solid now the benefit of evaporation is that it's a relatively quick and easy way to separate solid from a solution the issue though is that some solids will decompose when they're heated which we call thermal decomposition so even though we could use this technique to isolate our solid we'd end up breaking it down into something else this means that for solids that are susceptible to thermal decomposition we have to use a slightly slower technique called crystallization the first step is still to place our solution into an evaporation dish and heat it but this time we need to heat it more gently so we might use a water bath instead of a bunsen burner then once some of the solvent has evaporated and you start to see crystals forming in the solution we stop heating it and leave it to cool as the solution cools more crystals will start to form because solids are less soluble at colder temperatures next we'll have to filter out these crystals from the remaining solution using filter paper and funnel and then the last step would be to dry our crystals by either leaving them somewhere warm or warming them up in an oven anyway that's all for today so if you enjoyed it then please do give us a like and subscribe and we'll see you next time you