C1 Atomic Structure And The Periodic Table Flashcards
What is a mixture?
A substance in a liquid that doesnt dissolve like sand in water
What is a solution?
A substance in a liquid that does dissolve like sodium chloride salt and water
The salt is the solute and the water is the solvent
What does filtration do and explain how to do it?
It removes insoluble solids from mixtures
Place filter paper in a filter funnel and pour the mixture through it which should leave the insoluble solid behind
How do you seperate a solution?
Either evaporation or crystallisation
Evaporation - place the solution in an evaporating dish/crucible on top of a tripod and slowly heat the solution using a bunsen burner, this will cause the solution to evaporate and the remaining solution to become more concentrated and after a while crystals will begin to form due to it being highly concentrated and eventually all of the solvent will disappear leaving dry solid crystals behind
What are the pros and cons of evaporation?
It is relatively quick and easy to seperate the solid from the solution however some solids will decompose when heated which is called thermal decomposition so although you can use this method it will further breaking it down into something else
Give a method to perform crystallisation?
Place our solution into an evaporating dish and heat it more gently
So use a water bath instead of a bunsen burner
And once you see crystals forming in the solution and some of the solvent has evaporated you stop heating it and leave it to cool
And once it begins to cool, more crystals will begin to form as solids are less soluble at colder temperatures
Next you have to filter out the crystals from the remaining solution using filter paper and a funnel and then you have to dry the crystals by either leaving them somewhere warm or warming them up in an oven
