States of Matter Flashcards
What are the properties of solids?
Strong forces of attraction between particles, particles are packed very closely together in a fixed and regular pattern.
Atoms vibrate in position but can’t change position or move.
Solids have a fixed volume and shape and have high density.
Solid particles have only a small amount of energy.
What are the properties of liquids?
Weaker attractive forces in liquids than in solids, particles are close together in an irregular, unfixed pattern.
Move and slide past each other which is why liquids adopt the shape of the container they’re in and also why they are able to flow.
Fixed volume but not a fixed shape and have a moderate to high density.
More energy than those in a solid but less than gaseous particles.
What are the properties of gases?
No intermolecular forces, particles are in random movement and so there is no defined pattern.
Particles are far apart and move quickly in all directions, they collide with each other and with the sides of the container (this is how pressure is created inside a can of gas).
No fixed volume, since there is a lot of space between the particles, gases can be compressed into a much smaller volume.
Low density.
Gaseous particles have the highest amount of energy.
What are the changes of state?
Melting, Freezing, Evaporating/Boiling, Condensing
What is melting?
Melting is when a solid changes into a liquid.
When a solid is heated, its particles gain more energy
This makes the particles vibrate more - weakens the forces that hold the solid together
At a certain temp - particles have enough energy to break free from their positions
What is boiling?
Boiling is when a liquid changes into a gas.
When a liquid is heated - particles get even more energy
This energy makes the particles move faster - weakens and breaks the bonds holding the liquid together
At a certain temp - particles have enough energy to break their bonds
What is freezing?
Freezing is when a liquid changes into a solid.
This is the reverse of melting and occurs at exactly the same temperature as melting, hence the melting point and freezing point of a pure substance are the
same.
Water for example freezes and melts at 0ºC.
Requires a significant decrease in temperature (or loss of thermal energy) and occurs at a specific temperature which is unique for each pure substance.
What is condensation?
When a gas changes into a liquid, usually on cooling.
When a gas is cooled its particles lose energy and when they bump into each other, they lack energy to bounce away again, instead grouping together to form a liquid.
No energy is required for condensation to occur and it takes place over a range of temperatures.
How do you predict the state of a substances?
At temperatures below the melting point:
- The substance will be in the solid state
At temperatures above the melting point:
- The substance will be in the liquid state
At temperatures above the boiling point:
- The substance will be in the gaseous state.
