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How can energy transfers and energy storage within a system be analysed?
How can energy transfers and energy storage within a system be analysed?
The first law of thermodynamics relates changes in internal energy (U) to heat (Q) added to the system and work (W) done by the system: ΔU=Q−W
Work done by or on a system can be quantified through pressure (p) and volume changes (ΔV)
Energy storage is observed through changes in temperature, phase, or internal energy during thermodynamic processes.
How can the future evolution of a system be determined?
How can the future evolution of a system be determined?
The second law of thermodynamics states that the entropy (S) of an isolated system increases over time, driving the system toward equilibrium.
By analyzing energy transfers and entropy changes, we predict whether a system will undergo irreversible processes or maintain equilibrium.
In cyclic processes (like heat engines), the evolution depends on energy efficiency and entropy production.
In what way is entropy fundamental to the evolution of the universe?
In what way is entropy fundamental to the evolution of the universe?
Entropy measures the degree of disorder; as the universe evolves, total entropy increases, leading to greater randomness.
The arrow of time (the direction in which events naturally unfold) is defined by the increase of entropy.
The universe’s long-term fate is linked to entropy — ultimately heading toward maximum entropy and thermodynamic equilibrium (the "heat death" scenario).
Understandings
Understandings
that the first law of thermodynamics results from the application of conservation of energy to a closed system and relates the internal energy of a system to the transfer of energy as heat and as work
that the work done by or on a closed system when its boundaries are changed can be described in terms of pressure and changes of volume of the system
that the change in internal energy of a system is related to the change of its temperature
that isovolumetric, isobaric, isothermal and adiabatic processes are obtained by keeping one variable fixed
that adiabatic processes in monatomic ideal gases can be modelled
that cyclic gas processes are used to run heat engines
that a heat engine can respond to different cycles and is characterized by its efficiency
that the Carnot cycle sets a limit for the efficiency of a heat engine at the temperatures of its heat reservoirs
that entropy S is a thermodynamic quantity that relates to the degree of disorder of the particles in a system
that entropy can be determined in terms of macroscopic quantities such as thermal energy and temperature and also in terms of the properties of individual particles of the system (Ω is the number of possible microstates of the system)
that the second law of thermodynamics refers to the change in entropy of an isolated system and sets constraints on possible physical processes and on the overall evolution of the system
that processes in real isolated systems are almost always irreversible and consequently the entropy of a real isolated system always increases
that the entropy of a non-isolated system can decrease locally, but this is compensated by an equal or greater increase of the entropy of the surroundings
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