First Law of Thermodynamics

First Law of Thermodynamics

• The First Law of Thermodynamics applies energy conservation to thermal systems.
• The change in internal energy equals the heat added to the system, less the work done by the system: ΔU = Uf - Ui = Q - W.
• ΔU represents the change in internal energy.
• Q represents energy transferred to the system as heat, which can be positive or negative indicating heat gain or loss.
• W represents energy transferred from the system by work, and can also be positive or negative depending on whether work is done by or on the system.

Thermodynamic Processes

• A thermodynamic process occurs when a system's state changes.
• An isobaric process maintains constant pressure.
• An isovolumetric process occurs at constant volume.
• An isothermal process maintains constant temperature.
• An adiabatic process involves no heat transfer (Q = 0) into or out of the system.

Work Done in Thermodynamic Processes

• The work done on a gas during a volume change is given by: W = -∫(from Vi to Vf) P dV.
• In an isobaric process (constant pressure), the work done simplifies to: W = -P(Vf - Vi).
• For an isovolumetric process (constant volume), no work is done: W = 0.
• For an isothermal process with an ideal gas, work is: W = -nRT ln(Vf/Vi).
• In an adiabatic process with an ideal gas, work is: W = -nR(Tf - Ti) / (1 - γ), where γ = Cp/Cv.

Heat Transfer in Thermodynamic Processes

• Heat transfer in an isobaric process is: Q = nCpΔT.
• Heat transfer in an isovolumetric process is: Q = nCvΔT.
• In an isothermal process, temperature change is zero (ΔT = 0), internal energy change is zero (ΔU = 0), and heat equals work: Q = W.
• No heat transfer occurs in an adiabatic process: Q = 0.

First Law of Thermodynamics Summary

Heat Engines and the Second Law of Thermodynamics

• A heat engine converts thermal energy into other forms of energy.
• Heat engines operate by:
  • Receiving heat from a high-temperature reservoir.
  • Converting a portion of this energy into work.
  • Rejecting the remaining energy to a low-temperature reservoir.
• Thermal efficiency is e = Weng / |Qh| = 1 - |Qc / Qh|.
  • Qh is energy taken from the hot reservoir.
  • Qc is energy discarded to the cold reservoir.
  • Weng is the net work done.
• The Second Law of Thermodynamics states that no heat engine can completely convert heat into work.

Heat Pumps and Refrigerators

• A heat pump moves energy from a cold reservoir to a hot reservoir.
• Refrigerators use work to move energy from inside the refrigerator (Qc) to the warmer room (Qh).
• The Coefficient of Performance (COP) quantifies efficiency: COP = |Qc| / W.

Carnot Engine

• The Carnot engine is a theoretical engine with the highest possible efficiency operating in the Carnot cycle.
• The Carnot engine's thermal efficiency is: ec = 1 - Tc/Th.
• No real engine can exceed the efficiency of a Carnot engine operating between the same temperatures.
• The COP of a Carnot heat pump in cooling mode is: COPc = Tc / (Th - Tc).

Entropy

• Entropy measures a system's disorder.
• Higher disorder corresponds to higher entropy.
• The change in entropy is: ΔS = Q / T, where Q is heat transferred at temperature T.
• The entropy change for a Carnot cycle is zero because it's reversible.
• The Second Law of Thermodynamics (in terms of entropy) states that the total entropy of an isolated system always increases in an irreversible process.

Additional Notes based on image:

• Blic refers to an entity.
• Bardt Most is an entity.
• Irde refers to an entity.
• Jon Biebersusan Can and Merger Inge are entities that occurred in Hamas.
• London Taty and Pagkukuba Cakutta are entities, the latter of which also had a "Black hole Incident"
• "Labanan ng Prasey" and "Laboran sa Burar Robert" are battles or persons (translated as "Battle of Prasey" and "Laboran in Burar Robert")
• "Women Madings Vicmt to Orienteken trial Printe" or "Women Madings went to Orienteken trial Printe" implies travel and legal action (translation could be off, and "printe" is unsure)
• There is a diagram of an "Anglazation"
• "Sepoy Mutiny A revit agent the british" (translated "Sepoy Mutiny A revit agent the british"), the mutiny had a "Sepoy Choral extra hired by britain".
• "Mahatma Gahandi - Nan Valent prison de to be mign" may be the disposition of Mahatma Gahandi (unsure of translation).
• There were "reams wing the Sepay".
• Mitering happened because "British put on and pig fatin their bullet Comora pigs are a furt Bumagat ang mga linaRIONS na Kari"