Topic 2- States of Matter and Mixtures Flashcards
Solids…
Sting forces of attraction Fixed positions Lattice arrangement Don’t move Definite shape and volume Don’t have much kinetic energy Vibrate- the hotter the solid becomes the more the particles vibrate (causing solids to expand slightly when heated)
Liquids…
Some force of attraction
Free to move past each other (random motion) but tend to stick together
Don’t keep a definite shape
Keep the same volume
More energy than solid state but less energy than gas state
The hotter the liquid, the faster they move (more energy)
Gases…
No force of attraction
Free to move (random motion), travel in straight lines and only interact when they collide
Don’t keep a definite shape or volume
When the particles bounce of the walls of container they exert a pressure on the walls
More energy than liquid and solid states
Hotter they get, the faster they move because they have more energy meaning pressure increases
Chemical changes happen…
During chemical reactions, when bonds between atoms break and the atoms change places.
The atoms from the substances you start off with (the reactants) are rearranged to form different substances (the products)
Hard to reverse (compared to physical changes)
Pure substances…
Contain only one element or compound
A mixture is…
More than one compound or different elements that aren’t all part of a single compound
Purity can be tested for by using…
Melting points and boiling points
Every pure substance has a specific, sharp melting point and boiling point
Impure substance will…
Melt or boil gradually over a range of temperatures
Simple distillation is used to…
Separate out solutions
SEE PRACTICAL
Fractional distillation is used to…
Separate a mixture of liquids
Simple distillation method…
- Heat distillation flask with sample of sea water in
- The part of the solution with the lowest boiling point will evaporate first- the water
- The water vapour passes into the condenser and cools and condenses
- Water is collected in the beaker and salt left in the flask at the start
Fractional distillation method…
SEE REVISION GUIDE (IMPORTANT)
Filtration is used to…
Equipment/ method?
Separate an insoluble solid from a liquid
Filter paper in a funnel, the liquid runs through the paper and the residue left behind is the solid
Crystallisation is used to…
Method
(3 steps)
Separate a solvable solid from a solution
- Heat an evaporating dish containing the solution (the solution will get more concentrated as the water evaporates)
- When you see crystals or when some water has evaporated, leave the solution to cool
- Filter the crystals out of the solution and leave them to dry
Chromatography is used to…
Separate a mixture of soluble substances and identify them