10 public questions tagged with this topic.
**Energy transfer** first law ΔU = Q - W, W includes P-V work, shaft work, electrical work, Q includes conduction Fourier law, convection, radiation Stefan-Boltzmann, distinction important because work is controllable, heat spontaneous from hot to cold, entropy associated with heat not work, explaining why heat engine efficiency
Ref: NCERT > Physics Book > Thermodynamics > Work Heat Distinction and Energy Transfer Modes
**Cyclic process** system returns to initial state, ΔU=0 over cycle, net work W_net = area enclosed in P-V diagram, Q_net = W_net from first law ΔU= Q - W =0 => Q_net = W_net, clockwise cycle work done by system positive, counterclockwise work done on system negative, efficiency η = W_net/Q_in. A process is reversible if it can be reversed, returning both the system and surroundings to their original states without any net change elsewhere. This requires quasi-static conditions and no dissipative effects like friction. Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal W
Ref: NCERT > Physics Book > Thermodynamics > Cyclic Processes and Reversibility Concepts
**Gamma determination** γ = C_p/C_v, C_p - C_v = R, for monatomic f=3 C_v=3/2 R C_p=5/2 R γ=1.67, diatomic f=5 C_v=5/2 R C_p=7/2 R γ=1.4, adiabatic relation P V^γ = const allows γ determination from P-V measurements, slope of log P vs log V = -γ. A quasi-static process is infinitely slow, ensuring the system remains in thermal and mechanical equilibrium with its surroundings at every stage. This allows well-defined state variables (e.g., P , T ) and is an idealized condition for reversible processes. Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal W
Ref: NCERT > Physics Book > Thermodynamics > Adiabatic Processes and Gamma Determination
A process is reversible if it can be reversed, returning both the system and surroundings to their original states without any net change elsewhere. This requires quasi-static conditions and no dissipative effects like friction.
Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.
T₂ = 600 × (10/20)⁰.⁴ = 600 × 0.7579 = 454.74 K, Cv = R/(γ-1) = 8.314 / 0.4 = 20.785 J/mol·K, w = nCvΔ T = 2 × 20.785 × (454.74 - 600) = -6042 J.
Ref: NCERT Class 11 Chemistry > Chapter 5: Thermodynamics > Topic: Thermodynamic Terms - System Surroundings and Types of Systems
w = -nRT ln(P₁/P₂) = -1 × 8.314 × 300 × ln(1/0.5) = -2494.2 × 0.693 = -1728 J.
Ref: NCERT Class 11 Chemistry > Chapter 5: Thermodynamics > Topic: Thermodynamic Terms - System Surroundings and Types of Systems
For reversible isothermal expansion, w = -nRT ln(P₁/P₂) = -1 × 8.314 × 300 × ln(10/2) = -2494.2 × 1.6094 ≈ -4013 J .
Ref: NCERT Class 11 Chemistry > Chapter 5: Thermodynamics > Topic: Gibbs Energy and Gibbs Energy Change and Equilibrium
w = -nRT ln(V₂/V₁) = -2 × 8.314 × 300 × ln(10/5) = -2 × 2494.2 × 0.693 = -3455.6 J.
Ref: NCERT Class 11 Chemistry > Chapter 5: Thermodynamics > Topic: Bond Enthalpy and Entropy and Spontaneity
It occurs with infinitesimal driving force changes is the scientifically accurate answer to this question. Within the study of Kinetics and Thermodynamic, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of It occurs with infinitesimal driving force changes directly address what is being asked. Among the other options, It proceeds infinitely fast, There is a maximum entropy change, and It occurs only at equilibrium do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.
Ref: Campbell Biology, Urry et al., 12th Ed.
It occurs at equilibrium is the scientifically accurate answer to this question. Within the study of Thermodynamics, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of It occurs at equilibrium directly address what is being asked. Among the other options, It happens infinitely fast, It does not obey thermodynamic laws, and It has no energy change do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 1
