Physical Thermodynamics and Fluids Flashcards
What is the definition of heat?
Transfer of non-mechanical energy between a system and its environment.
What is heat related to ?
Total thermal energy of an object
What does an extensive property mean?
Extensive property means that it depends on the mass of the material
What is the formal definition of temperature?
it is the macroscopic measure of the average internal (thermal) energy of a system.
Related to average kinetic energy of molecules
Does temperature depend on amount of material?
No, it is an intensive
Does adding heat always increase temperature?
No not always, phase change can also happens
Compare a huge glacier to a red hot piece of charcoal,
what is the charcoals thermal energy and temperature compared to the glacier?
Higher temperature, yes
Higher thermal energy, no
Thermal energy depends on
What is the Zeroth Law of Thermodynamics?
The zeroth law of thermodynamics describes thermal equilibrium. When two objects of different temperatures are put together, the heat will flow until the objects have the same temperature
What are the three modes of heat transfer?
1) Conduction:
heat transfer through solids in contact (refer back to equation sheet)
2) Convection:
heat transfer via fluid circulation
(density differences)
3)Radiation
heat transfer by emission/absorption of electromagnetic energy
Why is an oven mitt useful?
What types of heat transfer is an oven mitt trying to prevent?
It is trying to prevent conduction.
In this case, length is increased, and K is decreased
If you add heat to something, what are the possible effects?
1) temperature increase
2) phase changes
3) Things can expand (on a hot summers day, pressure increases in tires can increase, decrease in the winter.
What does a closed system mean?
A closed system means an object that does not exchange matter with a system, but can exchange heat.
What does the internal energy of a closed system depend on?
The energy transfer into the system and the the work the system does on its surroundings.
What is work?
Work is the amount of force appliedover distance
Thereby, what would the formula for internal energy/change in internal energy be?
change in energy= heat energy added (Q)-Work done (W)
What is heat related to?
total thermal energy of an object
What is thermal energy?
Thermal energy is the energy in an object that gives is related to it’s temperature.
It is the measure of the total kinetic energy in a molecule
What is heat?
Heat is the transfer of thermal energy.
How are temperature and thermal energy related?
Temperature and thermal energy are related as thermal energy can affect temperature.
However, they are different in that thermal energy depends on the mass of an object, while temperature does not depend on the mass of an object.
Temperature is a measure of the average kinetic energy, while thermal energy is the measure of all the kinetic energy in a mass.
Thereby thermal energy is dependent on mass.
What is the internal energy of a system?
The total overall energy in a system. (Potential energy+kinetic energy+ chemical bond energy+ any other types of energy in a system)
How can you measure the change of internal energy in a system?
Delta E= Q-W
where Q= heat added to the system
W= the work done by system
This is the also the first law of thermodynamics.
Ideal gas law:
PV=nRT
what are the variables in the ideal gas law called (one term)
state variables
If two gases have the same state variables at the same time, they are called:
identical, in the same state