States of Matter and Mixtures Flashcards
Describe a solid
Strong forces of attraction which hold particles in fixed positions in a regular lattice arrangements
Don’t have much energy
Only vibrate round fixed positions
Describe a liquid
Some force of attraction between particles. They’re free to move past each other but tend to stick together
Don’t keep a definite shape
Particles are constantly moving with random motion
More energy than solid state
Describe a gas
Next to no force of attraction between the particles - they’re free to move
Don’t keep shape or volume
Highest energy
Expand when heated
What happens to the atoms in chemical reactions
They re-arrange to form different substances
What is a pure substance
A substance made up of one single element or compound
How can you test for purity
Testing melting points
Impurities lower melting point
What is fractional distillation used to do
Separate a mixture of liquids
What is filtration used to do
Separate an insoluble solid from a liquid
What is crystallisation used to do
Separate a soluble solid from a solution
What is chromatography used for
Separating a mixture of soluble substances and identify them
What is the mobile phase
Where the molecules can move
Always a liquid or gas
What is the stationary phase
Where the molecules can’t move
Can be a solid or a viscous liquid
What does the amount of time that the molecules spend in each phase depend on
How soluble they are (more soluble travel further)
How attracted they are to the stationary phase
What is a locating agent
A substance that you spray on your chromatogram if the chemicals are colourless
How to calculate the Rf value
Distance travelled by solute / distance travelled by solvent
