Chapter 14 - Thermal Physics Flashcards
Describe thermal equilibrium.
Objects are in thermal equilibrium when there is no net flow of energy between them.
What is the absolute scale of temperature?
A scale of measuring temperature that uses absolute zero and the triple point of water as its fixed points.
What is the triple point of a substance?
A specific temperature where the three phases of matter exist in thermal equilibrium.
Describe the structure of a solid.
-Strong forces between particles.
-Vibrate in fixed positions.
-Regular 3D structure, packed closely together.
Describe the structure of a liquid.
-Particles are free to move around.
-No fixed shape.
-Particles are still close together.
Describe the structure of a gas.
-Particles are far apart.
-Move at random speeds & directions.
-Almost no forces of attraction.
-Occupies a large volume compared to liquids.
-Collide with each other & container.
What is Brownian motion?
The continuous motion of small particles suspended in a fluid.
Define the internal energy of a substance.
The sum of a substance’s kinetic and potential energies.
Define absolute zero.
The lowest possible temperature, at which substances have minimum internal energy.
What happens when you increase a substance’s temperature?
Its molecules move faster.
What happens to a substance when it changes phase?
Temperature does not change, but electrostatic potential energy increases significantly.
Define specific heat capacity.
The energy required per unit mass to heat a substance by 1 Kelvin.
Define specific latent heat.
The energy required per unit mass for a substance to change phase while at constant temperature.
What is the difference between specific latent heat of fusion and specific latent heat of vaporisation?
Fusion is solid to liquid; vaporisation is liquid to gas.
How do you convert from ℃ to Kelvin?
T(K) ≈ θ + 273℃
