Thermodynamics Laws and Concepts Quiz

Laws of Thermodynamics

• Zeroth Law: Establishes a temperature equilibrium concept between systems.
• First Law: Energy conservation; the energy change in a closed system is equal to heat added minus work done.
• Second Law: In spontaneous processes, the total energy of the universe increases (ΔSuniverse > 0).
• Third Law: As temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.

Basic Thermodynamic Terms

• System: The part of the universe being studied.
• Surroundings: Everything outside the system.
• Boundary: The division between the system and surroundings.
• Homogeneous System: Uniform composition throughout.
• Heterogeneous System: Composed of two or more distinct phases.
• Open System: Exchanges both energy and matter with surroundings.
• Closed System: Transfers energy but not matter.
• Isolated System: No exchange of energy or matter with its surroundings.

Properties

• Intensive Property: Independent of system size (e.g., temperature, pressure).
• Extensive Property: Dependent on system size (e.g., volume, mass).

First Law of Thermodynamics

• Internal energy change (ΔE) is linked to heat (q) and work (W) through the equation ΔE = q - W.
• For expanding gas, total work done is calculated as W = P × ΔV.
• Energy changes must balance in a closed system—no perpetual motion machines can exist.

Enthalpy

• Defined as total heat content at constant pressure: H = E + PV.
• Change in Enthalpy (ΔH) is represented as ΔH = ΔE + PΔV.
• Substantial for calculations at constant pressure (ΔH = q).

Reversible Expansion

• Isothermal reversible expansion involves gradual changes in pressure.
• Work done during expansion expressed as W = -∫PdV.
• For ideal gases, work can also be represented with logarithmic functions of pressure (e.g., W = -nRT ln(P2/P1)).

Heat Capacity

• Molar Heat Capacity (Cp): dH/dT = Cp at constant pressure.
• Internal Energy Capacity (Cv): dE/dT = Cv at constant volume.
• Relation between heat capacities: Cp = Cv + R, where R is the gas constant (1.987 cal K–1 mol–1 or 8.314 J K–1 mol–1).

Second Law of Thermodynamics & Entropy

• Entropy increases in spontaneous processes (ΔSuniverse = ΔSsystem + ΔSsurroundings).
• Reversible processes maintain constant entropy (ΔSuniverse = 0).
• Entropy quantifies molecular disorder or randomness within a system.

Test your understanding of the laws of thermodynamics and basic terms related to thermodynamic systems. This quiz covers key concepts such as the Zeroth, First, Second, and Third Laws, along with definitions of various types of systems. Dive into the principles that govern energy and entropy in physical systems.