3. Thermodynamics EQUATIONS Flashcards
3 (Equation) What is the equation for length change based on a temperature of a solid?
∆L= αL∆T
∆L= change in length
α= coefficient of linear expansion (given)
L= original length
∆T= change in temperature
CHANGE A LOT
3 (Equation) What is the equation for volume change based on a temperature of a liquid?
∆V= αV∆T
∆L= change in length
α= coefficient of linear expansion (given)
L= original length
∆T= change in temperature
3 (Equation) What is the first law of thermodynamics?
∆U= Q-W
∆U= change in internal energy= positive: increase temperature= neg: decrease temp
Q= heat= +: heat flows into system, - : heat flows out of system
W= work= +: work is done by the system (expansion), -: work is done on the system (compression).
You can think of T as temperature, Q as heat, and W as pressure.
The first law of thermodynamics is a statement of conservation of energy: the total energy in the universe can never decrease or increase.
3 (Equation) What is the equation for temperature change without phase change?
q=mc∆T
q= heat
m= mass
c= specific heat value
T= change in temperature (generally Kelvin)
3 (Equation): What is the equation for an isothermal process, and what is an example?
Q = W because (ΔU = 0)
Isothermal means no temperature change.
ΔU= temperature
Q= heat
W= work (or pressure)
Temperature= heat - pressure
An example would be a boiling pot of water. It stays the same temperature.
3 (Equation): What is the equation for an adiabatic process, and what is an example?
Adiabatic= no heat exchange
ΔU = −W because (Q = 0)
Adiabatic= no heat exchange (A (absence diabtic= diablo- no heat)
ΔU= temperature
Q= heat
W= work (or pressure)
Example: Pot without a heat source, just being pressurized.
3 (Equation): What is the equation for an isobaric process, and what is an example?
Pressure is held constant.
Multiple forms.
A pot that is open to the air that is being heated.
It should be noted, something could be isobaric and isothermic.
3 (Equation): What is the equation for an isochoric process, and what is an example?
Isochoric= same volume, so there is no work
ΔU = Q because (W = 0)
An example is a pressure cooker with a lid. The volume is going to be the same.
3 (Equation) What is the equation for entropy?
ΔS= entropy
Key concept: The universe is a closed, expanding system, so you know that the entropy of the universe is always increasing. The more space that appears with the expansion of the universe, the more space there is for the entire universe’s energy to be distributed and the total entropy of the universe to increase irreversibly.
