⭐️SC1 and SC2 - States And Seperating And Purifying Flashcards
What are the three states of matter?
Solid, liquid and gas
What are the particles of a gas like?
Random, far apart and move quickly in all directions
What are the particles of a liquid like?
Random, close together and move around each other
What are the particles in a solid like?
Regular, close together and vibrate around fixed points
What is sublimation?
Going from solid to gas
What’s deposition?
Going from gas to a solid
What is a physical change?
Reversible change where only
the arrangements and movement and amount of energy stored is changed
How are particles attracted to each other?
By weak forces of attraction
What happens when a substance melts?
Some attractive forces are overcome with the heat energy and so cause it to form a liquid
What must happen for attractive forces to be overcome?
Energy must be transferred from the surroundings to the particle
If a substance is below melting point, the state is…
Solid
If a substance is between the melting point and boiling point the substance is…
Liquid
The substance is above the boiling point the state is…
Gas
Why does the temperature stay constant and when?
When boiling and melting as particles are escaping when boiling or breaking away from their fixed arrangement when melting
The composition of a pure substance…
Can’t change and is the same in all parts of a piece of the substance e.g. pure gold only has gold atoms
Compounds can’t be pure. True or false
False they can be pure
What is a pure substance?
A substance with a fixed composition in all its parts and can’t be separated into other substances using physical methods
What is a mixture?
Elements that aren’t chemically joined together so you can use physical processes to separate them
What’s the melting point?
The temperature at which particles gain enough energy to overcome weak forces of attraction and move further away from each other so the solid becomes a liquid
The difference between the melting point of a pure substance and a mixture?
Pure substance will melt at the same temperature until all the substance has changed so it will have one melting point as it had the same composition in all its parts but a mixture melts over a range of temperatures
What does it look like when a pure substance melts snd is plotted on a graph?
It has curves and stays on one temperature when it melts
Does it look like when an impure substance melts and is plotted on a graph?
The lines are sharp and the melting point is over a range of temperatures