Thermodynamics midterm Flashcards
What is a Generator
Electricity is generated by a shaft turning inside a generator. Coils of wire rotate inside a
magnetic field creating an electric field. This causes the electrons to flow in the wire creating a
current.
What is a turbine
Blades are connected to a rotor shaft and are propelled by the force of steam
What is a Boiler
A heat source that boils water into steam
James Prescott Joule
Determined the relationship between heat and work
Worked with lord kelvin to establish absoulute temperature scale
Joules Law: Heat produced by current flowing through a resistor
On his Gravestone: The number 772.55 is enscribed
What is the 1st Law of Thermodynamics
Energy cannont be created or destroyed, but it can be transferred from one form to another. Waste heat is always produced
Triple point
Temprature where water ice and steam can all exist 273.16k and 611.2pa
What is the second law of thermodynamics
Heat flows from hot to cold
What is the 0th law of thermodynamics
If two isolated systems are of equal temperature with a third system the two systems are equal in temperature as well
The state of a system
only two independent intensive properties are required to define a system TEMP AND PRESSUR, only for compressible systems
The state pf equilibrium
The system contains no driving forces, they experience no changes when theyre isolated from their surroundings
Thermal Equilibrium
Two bodies are in thermal equilibrium if they have the same temp
Quasi equilibrium
The process goes along a path that keeps it very close to equilibrium at all times. Slow enough to allow the system to adjust itself such that its properties change at the same rate
Thermal Expansion
The inceerease of an objects dimenstions as its temp increases
Closed system
No mass can cross the boundary but energy can
Isolated
Neither mass nor energy can cross the boundary
Intensive properties
independent of mass of the system
Extensive properties
Depends on size
Intensive extensive pairs
Thermodynamic variables tht multply to energy PRESSURE AND VOLUME TEMP AND ENTROPY, MOLES AND ENTHAPLY
What is Heat
The energy transferred between a system and its enviroment becasue of a temperature difference between them. it is path depeneant. The energy of the system will INCREASE if energy is added as heat Q
Work
The energy transfer associated with a force activing through a distance. Anything besides a temperature difference is work
the heat of transformation
the amount of energy per unit mass that must be transferred as heat
when a sample undergoes a phase transformation.
● The heat of vaporization - to go from the liquid state to the gas state, or vice-versa.
● The heat of fusion - to go from the liquid state to the solid-state, or vice-versa.
● Note: temperature vs. time graph of a liquid, the phase occurs at the substance’s
boiling/melting point, at this temperature will be flat.
Ludwig Boltzmann
● Created relationship between engineering and statistics.
● Hung himself after his work was not recognized
● Stated that at a given temp all ideal gas molecules have the same Kavg regardless of mass
Internal energy U
The sum of all microscopic forms of energy. (sensible latent chemical nuclear) Internal energy is a function of temp only (james joule)
Isothermal process
Constant temp
