Studied by 4 peopleDescribe particle arrangement of solid
Tightly packed, cant move but vibrate in their place
Describe particle arrangement of liquid
Close together, irregular arrangement, can flow past each other
Describe particle arrangement of gas
Far apart, irregular arrangement
How does density compare in solids, liquids and gasses?
Solids are most dense then liquid then gas
How does temperature affect the motion of particles?
Directly proportional
Increase in heat = increase in KE
How does the intermolecular force compare in solids, liquids and gasses?
Solids have the strongest then liquid then gas
What is the process from solid to liquid?
melting
What is the process from liquid to gas?
evaporation
What is the process from gas to liquid?
condensing
What is the process from liquid to solid?
freezing
What is the conversion from Kelvin to C?
Minus from K 273 to get C
What is the conversion from C to K?
Add 273 to C to get K
What is kelvin called?
Absolute zero
What is evaporation?
The escape of higher energy particles from the surface of a L to form a G, results in a decrease in T
When and where does evaporation occur?
At any T, only at the surface of the L
How do you increase evaporation?
Add heat
Increase SA
Increase air currents
Boiling vs evaporation?
What is the relationship between collisions and pressure?
Directly proportional
More collisions=more pressure/force exerted (they hit harder)
What happens every time a molecule collides with a wall?
Experiences a change in momentum
What happens if volume is decreased (compressed) and why?
Pressure increases (constant T. inversly prop)
Due to more collisions with walls
What happens if volume is increased (expanded) and why?
Pressure decreases (constant T, inversely prop)
Due to less collisions with walls
What happens if volume is increased? (constant P) and why?
T increase (directly proportional)
Because molecules move faster and more apart (thermal expansion)
What happens if volume is decreased? (constant P)
T decreases (directly proportional)
What devices removed air from a sealed container?
Vacuum pump
What happens to pressure if T of a gas is increased? (constant V) and why?
Pressure increases (pressure and T have a directly proportional rs due to increased heat=increase in ke/speed)
Give an equation relating P and V at a constant T
pV=constant OR P1V1=P2V2
p=Pa V=m³
What is thermal expansion?
When a material is heated it expands
What state of matter experiences most thermal expansion?
Gasses then L then S (bc G have most space to move)
What is Brownian motion?
Random and irregular motion of dust particles in the air
Why does Brownian motion occur?
Air molecules move freely, colliding with dust particles from all directions
Describe how T is measured by liquid in glass apparatus
As T rises/falls, the L expands/contracts
A scale is used to calibrate and convert the expansion to a T value
Give examples of fixed points used to calibrate thermometers?
Melting point of water = 0C
Boiling point of water = 100 C
What is sensitivity?
The change of output per unit charge of input
What is the sensitivity of a thermometer?
The change in length per degree change in T
How do you increase a thermometer’s sensitivity?
Bigger bulb
Narrower bore
Define range
The diff between the max and min values
How can a thermometer’s range increase?
Wider bore
Longer stem
Define linearity
When a change in put causes the same change in output
Where does a bimetallic strip bend towards when heated?
Upwards
What is internal energy?
The total energy stored by particles in a system
What kind of energy is stored in internal energy?
Kinetic and potential
How does heating affect internal energy?
It increases the internal energy (particles move more bc higher ke)
What does an increase in internal energy result in?
Increase in T or change of state
What is specific heat capacity?
The amount of energy needed to raise the T of 1 kg of an object by 1c
What does low SHC mean?
heats up and cools down quickly
Takes less energy to change its T
What does high SHC mean?
heats up and cools down slowly
Takes less energy to change its T
What is SHC formula?
E=mcT
How do changes in state look graphically?
What is conduction? (in non metals)
Transfer of heat through vibration of atoms with nearby atoms
What is conduction? (in metals)
Transfer of heat through vibration of atoms with nearby atoms and electrons move FREELY, thus heating up farther atoms
Why are metals conductors of heat?
Because of their free moving electrons (travel and spread their heat further)
In what kind of matter can conduction occur?
S and L
Describe process of conduction
S/L is heated
Particles vibrate more
Energy is trans. to adjacent molecules visa collisions, transf. heat from hot to cold regions
What is convection?
Transfer of heat THROUGH L and G, relies on thermal expansion and density
In what kind of matter can convection occur?
In fluids (L and G)
Describe process of convection
When a section of fluid is heated it become less dense
This causes it to rise
Denser (colder) fluid falls to take its place, heating it, causing it to rise
This sets up a convection current
Why cant heat NOT travel through a L by conduction?
Because molecules in L slide over each other, they don’t collide with each other frequently
What is radiation?
IR rays emitted from surface of any object as long as its HOT
What kind of materials can transfer due to radiation?
Any kind of material, a medium isnt required
What is Infared radiation?
IR is an electromagnetic wave
What are the best absorbers of IR
Black, dull surfaces (shiny white is worst)
What are the best emitters of IR?
Black, dull surfaces (shiny white is worst)
What factors effect the amount of IR emitted by a body?
T (higher=more IR)
SA (larger=more IR)
What is the best reflector?
Shiny white
Note
Flashcard