Filtration

• Filtration is used to separate an insoluble solid from a liquid. It is useful for separating sand from a mixture of sand and water, or excess reactant from a reaction mixture.  

  Filtration works because the filter paper has tiny holes or pores in it. These are big enough to let molecules and dissolved ions through, but not the much larger particles of undissolved solids. 
• Simple distillation separates a liquid from a solution 
• The cold water in the water jacket is needed or the whole thing fails. It is needed because once the water in the flask is boiled, the water turns into steam and gas is left. The cold water condenses the gas and allows it to turn back into water which then is clean and safe. The beaker at the end catches the water. Eventually, all that’s left is salt in the flask.