What is the kinetic (particle) theory?
All matter is made up of tiny particles that are constantly moving
Describe the properties of a sold?
- Strong force of attraction (between particles) Hold them close together (in fixed position) - forming a ‘regular lattice structure’
- Bc particles r fixed, they hold a definite shape & vol
- Can vibrate
What happens when we heat up a solid?
-Particles will gain more energy & start to vibrate even more (weakens the forces between them) —At their ‘melting point’ particles break free of the bonds
Turning solid to liquid
Describe the properties of a liquid?
-Free to move around & arranged randomly
-Weak forces of attraction (between particles) =
particles stick together & fairly compact =
have a ‘definite vol’
-Overall shape can change (flow to fit a container)
What happens when you heat up a liquid?
- Gains more energy (particles moves faster) - weakens forces holding particles together
- At their ‘boiling point’ will have enough energy to break bonds altogether - so liquid boils & evaporates into gas
Describe the properties of a gas?
- Forces of attraction is very weak (free to move around)
- Do not keep definite shape or vol instead will fill a container
- Constantly moving with random motion (travel in any direction)
What happens when we heat up a gas?
-Particle get more energy (move faster)
either they’ll - expand if container is expandable (i.e. ballon)
- if container is fixed pressure will increase
What happens when you cool a gas down?
-Wont have enough energy to over forces of attraction =
Bonds will form between particles - condensing gas into a liquid
What happen if you cool down a liquid?
-Wont have enough energy to over forces of attraction =
Even more bonds will form - fixing particles into place (turns liquid to solid)
When substance changes shape what is conserved?
mass
Describe & explain if changes of state are physical or chemical?
- Changes of state r not same as chemical changes bc states r reversible
- If state was chemical then it would be irreversible
Define closed system
A physical system that doesn’t exchange any matter with its surroundings
What happens if you’re working in a closed system? (particles)
-Changes in state won't change the mass (still the same n.o of particles) BUT Density will change: solids = highest density liquids = lower density gas = lowest density
