SC1/2 - States of Matter / Separating & Purifying Substances Flashcards
What are the 3 states of matter?
Solid
Liquid
Gas
What are the particle arrangments and movement of each of the 3 states?
Solid - tightly packed, regular arrangement and they vibrate around a fixed position
What is it called when:
1 - Solid → Liquid
2 - Liquid → Gas
3 - Gas → Liquid
4 - Liquid → Solid
5- Gas → Solid
6 - Solid → Gas
- Melting
- Evaporation
- Condensation
- Freezing
- Deposition
- Sublimation
What are the forces which have to be overcome to achieve a state change?
Force of attraction
What is a substance which can’t be changed and is the same in all parts of it?
Pure
What is a substance made of elements or compounds chemically joined together and can be separated using physical methods?
Mixture
What are examples of mixtures?
Juice
Chocolate
Cake
Exam Q - Explain why mixtures have a range of melting points but pure substances have precise melting points (2 marks)
Mixtures have different substances inside them, and each one has a different melting point whereas, in a pure substance, there is only one type of element or compound which is chemically bound, so it has precise melting and boiling points.
What can be used to separate mixtures from insoluble substances?
Filtration
What is a mixture made of solutes (dissolved substances) in a solvent?
Solution
What is crystallisation?
When the solvent is evaporated out of the solution, leaving behind solutes.
What is it called when a solution contains the maximum amount of solute that can dissolve in the solvent?
A saturated solution.
What is chromatography?
When you separate coloured substances of a mixture.
What is the mobile and stationary phase?
Mobile - The solvent
Stationary - Part of paper where the solvent moves up.
How do you calculate the Rf value?
distance moved by spot / distance moved by solvent
What are the 3 uses of chromatography?
To identify different substances by calculating the Rf.
Distinguish between our and impure substances.
Identify substance by comparing it to other patterns of known ones
What 2 ways are there to produce pure water in a lab?
Simple still
Distillation
What is fractional distillation?
When a fractional column is connected to a distillation setup to separate 2 or more liquids with different boiling points. The liquids with lower boiling points travel up the column first as it get hotter, letting you separate the liquids.
How does a simple still work?
By heating liquid water and evaporating the pure water into another tube to condense it. It is not very efficient as lots of water is lost
How does a distillation work?
By heating the liquid water (with anti-bumping granules) and evaporating it into a condenser which efficiently cools it down with minimal loss of water. The water is condensed and goes to a flask.-
What are the uses of fractional distillation?
It is used in separating crude oil
Making alcohol
Separate gases in the air like liquid air.
What are the stages of making water safe to drink?
Sieve out all the big pieces
Sedimentation - small particles settle down
Filtration - sand and gravel to get rid of soluble substances
Chlorination - disinfect the water
