Thermal Physics Flashcards
What are the 6 state changes?
- Solid to Liquid - Melting
- Liquid to Gas - Boiling/Evaporation
- Gas to Liquid - Condensation
- Liquid to Solid - Freezing/Solidification
- Solid to Gas - Sublimation
- Gas to Solid - Deposition
What is the temperature at Absolute Zero?
0 Kelvin
-273°C
What is Absolute Zero?
The point at which atoms have the least possible kinetic energy
What is the Kinetic Model of Matter
The study of the relation between average internal kinetic energy and temperature
What is the effect of a change in temperature on pressure?
When there is a constant volume
T ∝ P
Directly proportional
What is the effect of a change in volume on pressure?
When there is a constant temperature
T ∝ 1/P
Inversely proportional
What is the formula for the relationship between pressure and volume?
pV = constant
p = Pressure (Pa)
V = Volume (m3)
Def. Internal energy
A measure of the average kinetic energy of the particles in a substance
How does internal energy present istelf?
Temperature
Def. Specific Heat Capacity
The energy needed to the change the temperature of a unit mass by a unit temperature
What is the formula for Specific Heat Capacity?
C = ΔE/(mΔT)
C = Specific Heat Capacity(J/(kgK) or Jkg-1K-1)
ΔE = Change in Energy (J)
m = Mass (kg)
ΔT = Change in Temperature (K)
Explain the process of evaporation
Wording is important
- Occurs when a liquid turns into a gas
- The liquid does not need to boil for evaporation to occur
- Particles need a certain amount of kinetic energy to escape the surface of the liquid
- When a particle escapes the surface, the average energy of the liquid left behind wil decrease
What are the three factors that affect evaporation?
- Temperature
- Surface Area
- Removal of vapours from liquid surface
How does surface area affect evaporation?
An increase in surface area will lead to an increase in evaporation because a larger surface means more particles can evaporate at once
How does temperature affect evaporation?
An increase in temperture will lead to an increase in evaporation as average kinetic energy of particles is increased so they are more likely to evaporate
How does the rate of removal of vapours from the liquid surface affect evaporation?
As this rate increases, evaporation increases because the vapours will make it harder for evaporation to occur, slowing the rate of evaporation
What is Conduction?
A transfer of thermal energy that occurs in solids in which particle vibration, ineternal kinetic energy, is transfered to neighbouring particles.
Term for
Poor conductor
Insulator
What main factor makes a good conductor?
Delocalised electrons which have a very low specific heat capacity so kinetic energy can be transfered quickly
What is the experiment to measure the conductivity of a metal?
Heat a bar of the material to which thumbtacks are attached with vaseline at regular intervals
What is Convection?
A transfer of kinetic energy that occurs in fluids (liquids and gases) by the diffusion of particles carrying internal kinetic energy throughout the fluid
Describe the process of convection
- Water close to a heat source gains thermal energy and becomes less dense
- The less dense, hot water rises and coller water replaces it
- As the water rises, it cools, and sinks back down, replacing hot water
- The cycle repeats
What is Radiation?
A transfer of energy that can occur in a vacum, normally by infrared waves
What are the properties of black materials in terms of radiation?
- Good thermal energy absorbers
- Bad radiation emitters
