topic 2 - states of matter Flashcards
Arrangement of particles in different states of matter:
Solid: regular
Liquid: random
Gas: random
Particle movement in different states of matter:
Solid: fixed position, can vibrate
Liquid: move around each other, still connected
Gas: moves quickly in all directions
Relative energy in particles of different states of matter:
Solid: Low
Liquid: Medium
Gas: High
What are physical changes?
Changes between states of matter
Solid —> Liquid
Melting
Liquid —> Gas
Boiling/ Evaporating
Gas —> Liquid
Condensing
Liquid —> Gas
Freezing
Stages of melting and boiling:
- Substance heats up
- Particles gain energy
- Forces between particles weaken
- Particles break free from positions
Stages of condensing and freezing:
- Substance cools down
- Particles lose energy
- Forces between particles strengthen
- Particles held in position
What is a pure substance?
A substance containing only one element or compound. In everyday use it means clean or natural.
What is a mixture?
An impure substance, made up of different elements or compounds that aren’t chemically bonded together
Difference between physical changes and chemical reactions
Physical changes: don’t alter what a substance is made of, only it’s state
Chemical reactions: create new substances by rearranging atoms
Predict the physical state of a substance under specified conditions, given suitable data
Using data like temperature and pressure we can predict whether a substance is a solid liquid or gas under specific conditions
How do you use melting point data to distinguish between pure substances and mixtures
Pure substances have a sharp boiling/melting point. Whereas mixtures melt gradually over a range of different temperatures.
Fractional distillation (equipment/ purpose)
Equipment: mixture of liquids, fractioning column, thermometer, condenser
Purpose: similar to simple distillation separates substances with closer BP’s using a fractionating column for better separation
Simple distillation (equipment/ purpose)
Equipment: solution, thermometer, condenser, beaker
Purpose: Separates substances with differing BP’s by heating and collecting the vapours of lower boiling components
Filtration (equipment/ purpose)
Equipment: filter paper, solution, beaker
Purpose: used to separate solid products, or purify a liquid by removing insoluble impurities
Crystallisation (equipment/ purpose)
Equipment: source of heat (Bunsen burner), solution
Purpose: separates soluble salts from solution by cooling, separating dissolved solids
Paper chromatography (equipment/ purpose)
Equipment: filter paper, pencil, mixture, watch glass, solvent
Purpose: used to separate a mixture of soluble substances
When should you use distillation?
Different boiling points, or volatile substances
When to use filtration?
Solid- liquid separation
When should you use crystallisation?
If a component forms crystals in a solvent
When should you use chromatography?
Different solubilities
