Particle Model Flashcards
Solids
Particles close together
Arranged in regular pattern
Vibrate (but don’t move from place to place)
Liquids
Particles close together
Not arranged in regular pattern
Can move around each other
Can flow
Gases
Particles very far apart Not arranged in any pattern Move very rapidly Can flow Compressible
Density
Mass of a material for a given volume
Density formula
rho = m/v
Density in Solids
Usually have very high density - particles packed together closely (have a lot of mass for their volume)
Density in liquids
Usually have high density - particles are close together (have a lot of mass for their volume)
Density in gases
Low density - particles are very far apart (have a small mass for their volume)
Changes of State
Mass is conserved (not adding or taking away particles)
Physical change - material recovers its original properties if change is reversed (unlike chemical changes)
Melting (solid to liquid), boiling (liquid to gas), sublimating (solid to gas)
condensing (gas to liquid), freezing (liquid to solid), deposition (gas to solid)
Heating & Cooling
Heating increases internal energy
Cooling reduces internal energy
Measuring density
RP 5
Measuring density
RP 5
- Measure object’s mass
- Find object’s volume - easy if regular e.g. cuboid
- If not get eureka can, fill it above spout, let water drain out
- Place empty measuring cylinder below spout
- Place in object, once spout stops dripping, volume of water in measuring cylinder is volume of object
- Calculate density
Object can’t float
Measuring density of a liquid
RP 5
- Place a measuring cylinder on a balance at 0
- Pour 10ml of liquid, record mass
- Pour another 10ml, record total volume & mass. Repeat until cylinder is full
- For each set of measurements, find density - will give precise density of liquid
