Zusammenfassung der Ressource
States of Matter
- Liquid
- Closely compact - still move
- Particles slide over one another
- Forces of attraction are less effective than solid
- Fixed volume, takes shape of container.
- Have more kinetic energy than solid
- Solid
- Strong forces of attraction
- Cannot be compressed
- Regularly arranged
- Fixed volume and shape
- Particles are closely compact
- Particles don't move they vibrate around a fixed point
- Have least kinetic energy
- Gas
- Have most kinetic energy
- No fixed shape or volume
- No arrangement
- Move randomly
- Almost no forces of attraction
- Interconversions
- Solid and Liquid
- Solid to Liquid = Melting
- Heat a solid, energy provided makes particles vibrate faster eventually vibrate
so fast that the forces of attraction become weak and are no longer strong
enough to hold particles together. Solid melts. As liquid particles have more
kinetic energy so solid particles has to be supplied with kinetic energy to
convert to a liquid. Melting Point - temperature at which solid melts.
- Liquid to Solid = Freezing
- Liquid cooled, particles move slowly, force of attraction will hold
the particles together. Freezing Point: Temperature at which
liquid freezes
- Liquid and Gas
- Liquid to Gas = boiling / evaporation
- Boiling
- Occurs when a liquid is heated so strongly so that particles
are moving fast enough to overcome all the forces of
attraction between them.
- the stronger the forces of attraction, the higher the boiling point
because more energy is needed to overcome these forces of
attraction.
- If gas is cooled, the particles eventually move
slowly enough that the forces of attraction
between them start to form and hold them
together as a liquid. The gas condenses
- Evaporation
- In any liquid or gas, the average speed of the particles
varies with temperature. But at each temperature,
some particles will be moving faster than the average.
- Some very fast particles at the surface of the liquid have
enough kinetic energy to overcome forces of attraction -
they will break away to form a gas.
- If a liquid is in a closed container, particles in the gas will be
colliding with the particles at the surface of liquid. If they are
moving slowly enough then they will be held by forces of
attraction and become part of liquid.
- In a closed container evaporation and condensation will occur at same time.
- Gas to Liquid = Condensation
- Difference between Boiling and Evaporation
- Evaporation occurs at any temperature, but boiling occurs at one
temperature - the boiling point of liquid.
- Gas and Solid
- Gas to Solid = Deposition
- Solid to gas = Sublimation
- Very few substances can change
directly from a solid to gas or gas to
solid, at normal pressure.
- Example : Carbon dioxide. At ordinary pressure there is no such thing as liquid
carbon dioxide - it directly turns from solid to a gas.
- Working out physical state of a substance at a
particular temperature
- A substance below its melting point = SOLID
- Between melting point and boiling point = LIQUID
- Above its boiling point = GAS
- Diffusion
- Definition: The random movement of gas or liquid particles from
an area of high concentration to an area of low concentration
- Gas particles diffuse quicker than liquid particles because
the particles move faster and are already more spread out
- Particles in liquid are much closer so there is less space for particles
to move without colliding with one another
- Solid particles do not diffuse because they do not move
out of position
- Lighter particles diffuse faster than heavier particles