Definition System and Difference between open, closed and isloated?
A thermodynamic system is a body of matter and/or radiation separate from its surroundings that can be studied using the laws of thermodynamics.
open system: matter and energy are exchanged
closed system: energy is exchanged
isolated system: no matter or energy is exchanged
Adiabatic process?
no heat is added or removed from the system
Definition Heat?
Heat (Q): energy (in transit) transferred because of a temperature difference
Definition Work?
Work (W): all other forms of energy (in transit) transferred
(mechanical, electrical, magnetic etc.)
Reversible vs Irreversibel process?
Reversible process: the initial state of the system can be restored with no observable effects in the system or the surroundings
Irreversible process: cannot be undone by exactly reversing the changes operated without other effects.
Every real process is irreversible
What is the first law of thermodynamics?
(for closed systems)
The change in internal energy is the change in work and heat energy.
The internal energy is a state function (=not a description of a process)
What is a closed system?
A closed system does not have an matter exchange.
A closed system does have an energy exchange.
What is an open system?
An open system has a matter and energy exchange.
How are which variations of quantities noted in thermodynamics?
How is enthalpy defined and what does it say about the needed energy of a reaction?
H=U+PV
if H is greater than 0 the reaction is endothermic (=needs energy)
if H is lower than 0 the reaction is exothermic (=releases energy)
(for open systems, expressed in enthalpy)
The internal energy is a function of the work and heat energy and the mass times enthalpy balance.
What defines a stready state?
In a steady state the internal energy does not change even thugh there is a energy and mass transfer.
Examples are turbines and chemical reactors.
This leads to the following relation:
Define the heat capacity.
The heat energy required to change the Temperature.
The heat capacity is a material property.
The heat capacity is a temperature function.
heat capacity at constant volume?
U and V are molar quantities in this equation
heat capacity at constant pressure?
H is a molar quantity in this equation
What is the Joule-Thompson coefficient?
Which relations result form the ideal gas equation for an ideal Gas?
How does the ideal Gas equation change for a non ideal Gas?
Which relations can be derived from the first law of thermodynamics for adiabatic systems?
How is Volume work calculated?
How does one calculate the enthalpy change at certain temperatures?
How do you calculate the forming enthalpy of components
What is the difference entropy wise for a reversible and irreversible process?
reversible: ΔS=0
irreversible: ΔS>0
What are the idealisations for an ideal gas?
negligible volume of gas particles
no intermolecule forces
constant kinetic energy
Random elastic collisions
Uniform distribution
no phase transitions
Zuletzt geändertvor einem Jahr
