Filtration And Crystallisation. Flashcards
Define “filtration”.
The process of removing insoluble substances from a liquid by allowing them to pass through filter paper.
Define “crystallisation”.
The process of forming solid crystals from a solution.
What does “saturated” mean?
No more solute is able to be dissolved by the solvent at that temperature.
What is a solute?
The substance (solid) that does dissolve.
What is a solvent?
The substance (liquid) that does the dissolving- it is the dissolving medium.
What does “soluble” mean?
That a substance is able to dissolve in a particular solvent.
What is the filtrate?
The substance that passes through the filter paper.
What is the residue?
The substance that stays on the filter paper.
What are the steps to carry out Crystallisation?
1) A solution is placed in an evaporating basin and heated slowly/gently with a Bunsen burner.
2) Do so until you start to see crystals.
3) Leave it to cool.
4) Solids are less soluble at cold temperatures, so more crystals will begin to form.
5) Filter the crystals out and dry them in a warm oven/leave them somewhere warm/pat them dry with filter paper.
What are the steps needed to carry out Filtration?
1) Get a beaker containing a liquid and a substance that has not dissolved in it.
2) Flute the filter paper and place it into a funnel.
3) Place this into a conical flask.
4) Slowly pour the mixture onto the filter paper.
5) The substance will collect on the filter paper as residue, and the liquid will pour into the conical flask.
Why is Crystallisation successful?
If a saturated hot solution is allowed to cool, the solute is no longer soluble in the solvent as solubility drops with lowered temperature, so crystals will be formed.
Why is Filtration successful?
The filter paper has tiny, microscopic holes that the solid particles will not be able to pass through, but the smaller particles of the solvent can due to its smaller size.
How would you flute filter paper and why?
- fold to crease the quarter sections.
- food to crease the eighth sections.
- this is the accordion shape.
- open filter cone.
This is to increase surface area, so filtration occurs quicker.
