C1.3 - Separating Mixtures (Finished) Flashcards
What is a mixture?
Two or more substances mixed together but not chemically combined together
What are the compositions like in compounds and mixtures?
Compound: fixed compositions (ratio of elements present doesn’t change)
Mixtures: No fixed composition (proportions depend on amount of each substance)
What is a compound?
Two or more substances chemically bonded together
How do you separate the elements of a compound?
With a chemical reaction
What is filtration used to separate?
Separating substances that are insoluble in a solvent from ones that are
How do you perform crystallisation?
1) Pour solution into an evaporating dish and heat the solution
2) When salt crystals start to form, remove from heat
3) Leave the solution (if water) for the water to evaporate off at room temperature
What is a soluble solid?
A solid that can be dissolved
What is (simple) distillation used to separate?
A liquid from a solution
What is the problem with (simple) distillation?
The liquids must have very different boiling points to prevent them from both evaporating at the same time, re-mixing
How does a condenser work?
Cold water circles around a tube, cooling it down and condensing any vapour in it
How does (simple) distillation work?
1) Solution is heated in a flask
2) The part of the solution with the lowest boiling point will evaporate
3) The vapour goes up and gets condensed in a condenser
4) The liquid is then collected and the rest of the solution is left behind in the flask
Name the 4 techniques for separating mixtures?
Filtration, crystallisation, distillation, chromatography
What do you differently in evaporation than crystallisation?
You evaporate off all the water on the bunsen burner
Name the part that goes on top of a tripod?
Gauze
