Thermal physics Flashcards
Define heating
The transfer of energy from a region of higher temperature to one of a lower temperature
Define thermal equilibrium
A state in which there is no net flow of thermal energy between two systems is considered to be in thermal equilibrium
Define triple point
A specific temperature and pressure where the three phases of matter (solid, liquid and gas) can exist in thermal equilibrium
Define Celsius scale
A scale for measuring the temperature that has units degrees Celsius and that is defined by the freezing point and boiling point of pure water at atmospheric pressure
Define absolute scale of temperature
A scale of measuring temperature based on absolute zero and the triple point of water. Unit is Kelvin
Define internal energy
The sum of the random distribution of kinetic and potential energies associated with the molecules of a system
Define kinetic model
A model that describes all substances to be comprised of atoms molecules or ions that are arranged dependent on the phase of the substance
Define a solid
Highly ordered, closely packed atoms or molecules with very strong electrostatic force of attraction between them. The two can have small vibrations, and therefore have kinetic energy
Define liquid
No fixed shape, but atoms or molecules still closely packed. Atoms and molecules can flow past each other but there is still electrostatic forces acting between them. Higher kinetic energy than solids
Define gas
No fixed shape, atoms and molecules are far apart from each other. Negligible electrostatic force, so can ignore. Therefore atoms and molecules are free to move past each other unless they collide head on. Gaseous atoms or molecules have high speed and therefore high kinetic energy
Brownian motion
The continuous and random movement of particles suspended in a fluid, visible under a microscope
Specific latent heat of fusion
The amount of energy required to change the phase of 1kg of a substance from a solid to a liquid
Specific latent heat of vaporisation
The amount of energy required to change the phase of 1kg of a substance from a liquid to a gas
Mole
The amount of substance that contains as many particles as exactly 12.0g of carbon-12
Ideal gas
A had that had internal energy only in the form of random kinetic energy
