Thermodynamics Overview

Thermodynamics

• Thermodynamics is the study of energy and its transformations.
• First Law of Thermodynamics: Conservation of energy.
• Thermodynamic property examples include pressure.
• System boundary: An imaginary or real surface separating the system from its surroundings.
• Closed system: Only energy can cross the system boundary.
• Zeroth Law of Thermodynamics: Helps with temperature measurement.
• Work done by a system: The system does work on the surroundings.
• Adiabatic process: Process without heat transfer.
• Second Law of Thermodynamics: The entropy of an isolated system always increases.
• SI unit of heat energy: Joule.
• Isochoric process: Constant volume.
• Specific heat: Heat required to raise one mole of a substance by 1 Kelvin.
• Isothermal process: Constant temperature.
• First Law relates heat, work, and internal energy.
• Isobaric process: Constant pressure.
• Second Law implication: Perpetual motion machines are impossible.
• Open system: Allows both mass and energy transfer.
• Thermodynamics primarily focuses on thermal systems.
• Entropy: Measures disorder or randomness in a system.
• Extensive property: Temperature is not an extensive property.

Other Concepts

• Net change in internal energy for a cycle: Zero.
• Path-dependent quantity: Work.
• Isothermal process: Constant temperature.
• Absolute pressure with vacuum reading: 70.6 kPa.
• Pressure on a diver at 30 m depth: 410 kPa.
• Temperature in Rankine: 540.60 R.
• Equal values for °F and °C: 26.67°C and 50°F.
• Temperature difference in heater: 45.55°C.
• Heat to increase air temperature: 2500 kJ.
• Final volume with pressure change: 40 liters.
• Density of air under given conditions: 1.2 kg/m³.
• Specific volume example: 1.2 m³/kg.
• Atmospheric pressure equivalent: 14.7 psi.
• Ideal gas constant (R): Universal gas constant.
• Boyle's Law relationship: Inversely proportional to volume.
• Charles' Law volume relation: Directly proportional to temperature.
• Avogadro's Law volume relation: Number of moles.
• Ideal gas assumption: Intermolecular forces are negligible.
• Pressure increase effect on volume: Decreases.
• Gay-Lussac's Law relates: Temperature.
• Volume effect with increased moles: Increases.
• Ideal gas assumption violation: Gas molecules lose energy upon collision.
• Volume doubling effect on pressure: Halves.
• Kinetic energy example: A moving car.
• Potential energy example: A compressed spring.
• Mechanical energy example: A spinning wind turbine.
• Energy associated with temperature: Thermal energy.
• Spring energy type: Elastic potential energy.