Physics and Math Ch3 Flashcards
Zeroth Law of thermodynamics
- Objects are in thermal equilibrium when they are at the same temperature
- objects in thermal equilibrium experience no net exchange of heat energy
Temperature
a qualitative measure of how hot or cold an object is
- related to the average kinetic energy of the particles that make up a substance
Thermal expansion
describes how a substance changes in length or volume as a function of the change in temperature
Heat
The transfer of thermal energy from a hotter object with higher temperature to a colder object with lower temperature
Absolute zero
the theoretical temperature which there is no thermal energy
- zero in kelvin system
Coefficient of linear expansion
A constant that characterizes how a specific material’s length changes as temperature changes
Coefficient of volumetric expansion
A constant that characterizes how a specific material’s volume changes as the temperature changes
State functions
thermodynamic properties that are a function of only the current equilibrium state of a system
- Ex: pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, entropy
Process functions
The path taken to get from one state to another
First law of thermodynamics
The total energy in the universe can never decrease or increase
- conservation of energy
Specific heat
The amount of energy necessary to raise one gram of a substance by one decree C or K
What is the specific heat of water
1 cal/g/K
Heat of transformation
During a phase change, heat energy causes changes in particles’ potential energy and energy distribution, but not kinetic energy
- no change in temp
Isothermal process
The temperature is constant and the change in internal energy is therefore 0
Adiabatic process
No heat is exchanged
Isobaric process
the pressure is held constant
Isovolumetric process
the volume is held constant and the work done by or one the system is 0
Second law of thermodynamics
In a closed system, energy will spontaneously and irreversibly go from being localized to being spread out
Entropy
A measure of how much energy has spread out or how spread out energy has become
Microstates relation to entropy
As the number of microstates increases, the potential energy of a molecule is distributed over that larger number of microstates, increasing entropy.
Natural Processes
are irreversible
Conduction
The direct transfer of energy from molecule to molecule through molecular collisions
Convection
The transfer of heat by the physical motion of a fluid over a material
- only liquids and gases can transfer heat by this means
Radiation
the transfer of energy by electromagnetic waves
- transfers energy through a vacuum
