Year 13 - Thermal Physics Flashcards
Absolute Zero
Absolute zero is the temperature at which the mean kinetic energy of molecules is zero, E.g. the particles are not moving. It is therefore a theoretical temperature.
Avogadro’s number (NA)
The number of atoms in 12g of carbon-12.
Boltzmann Constant
A constant relating the average kinetic energy of the particles in a gas, to the temperature of the gas in Kelvin.
Boyle’s Law
Pressure is inversely proportional to Volume when under a constant Pressure.
Brownian Motion
The motion is caused by collisions between air molecules and smoke particles.
Charles’s Law
Volume is directly Proportional to Temperature when under constant Pressure
Closed System
Does not allow transfer of energy or matter in or out of the system.
First Law of Thermodynamics
The energy of the universe remains the same. Though it may be exchanged between the system and the surroundings, it cannot be created or destroyed.
Ideal Gas
A gas that meets the ideal gas assumptions. All the gas laws are based on ideal gases.
Ideal Gas Assumptions
1) Volume of particles is negligible compared to the volume of the container (1)
2) Collision time is negligible (1)
3) Collisions are elastic (1)
4) There are negligible intermolecular forces (1)
5) large number of particles (1)
Internal Energy
The total kinetic and potential energies of all of the particlesin a system.
Kelvin
An absolute temperature scale that starts at absolute zero (0K = -273°C).
Kinetic Theory Model Assumptions
1) Volume of particles is negligible compared to the volume of the container (1)
2) Collision time is negligible (1)
3) Collisions are elastic (1)
4) There are negligible intermolecular forces (1)
5) large number of particles (1)
Molar Gas Constant, R
A fundamental constant, used in the ideal gas law. R= 8.31.
Molar Mass
The mass of one mole of a substance.
Molecular Mass
The mass of one molecule of a substance.
Open System
Energy can be transferred between the system and its surroundings.
Pressure Law
Pressure is directly Proportional to Temperature when under constant Volume.
Specific Heat Capacity
The amount of energy required to change the temperature of 1kg of a substance by 1 Kelvin.
Specific Latent Heat of Fusion
The amount of heat energy required per unit mass, to change a substance from a solid to a liquid without any change in temperature.
Specific Latent Heat of Vapourisation
The amount of heat energy required per unit mass, to change a substance from a liquid to a vapor without any change in temperature.
System
A collection of objects (or smaller systems) that can be identified e.g. a car engine or a cup of tea.
Thermal Equilibrium
No net flow of (thermal) energy (between two or more bodies) (1), bodies at same temperature (1), (kinetic) energy is exchanged in molecular collisions (1), until average kinetic energy of all molecules is the same (1).
Zeroth Law of Thermodynamics
If two thermodynamic systems are both in thermal equilibrium with a third system, then the twosystems are also in thermal equilibrium.
