C14 Thermal Physics Flashcards
1
Q
What is the triple point of a substance?
A
- One specific temperature and pressure where all three phases of matter exist in thermal equilibrium.
- Meaning there is no net transfer of thermal energy between the phases.
2
Q
Describe the flow of thermal energy between two objects, e.g. your body and cold air.
A
- There is a net flow of thermal energy from the hotter object to the colder one.
- Thermal energy transfers from your body to the cold air, cooling your body, and heating the air.
3
Q
Temperature of objects in thermal equilibrium
A
- Objects in thermal equilibrium must be at the same temperature.
- Meaning there is no net flow of thermal energy between them.
4
Q
Define internal energy
A
The sum of the randomly distributed kinetic and potential energies of atoms or molecules within a substance.
5
Q
What happens to internal energy at absolute zero?
A
- The kinetic energy of the particles is zero, but there is still electrostatic potential energy.
6
Q
State the 0th law of thermodynamics
A
- If two objects are each in thermal equilibrium with a third, then all three are in thermal equilibrium with each other.
7
Q
State atmospheric pressure
A
1.01 x 10^5 Pascals
8
Q
What is the issue with the Celsius scale?
A
- Temperature can vary significantly depending on the surrounding atmospheric pressure.
9
Q
What is the absolute/thermodynamic temperature scale?
A
- This scale uses the triple point of pure water and absolute zero as its fixed points.
- Units kelvin (K)
10
Q
Define Brownian Motion
A
- Brownian motion is the random, erratic movement of tiny particles suspended in a fluid.
- This motion is caused by the constant, uneven collisions of the fluid’s molecules with the particles.
11
Q
Electrostatic forces between particles in the different phases
A
Gas: Zero electrostatic potential energy, no electrical forces between particles.
Liquid: Negative value for electrostatic potential energy.
