A. Snow melts into water
B. A gas expands spontaneously from high pressure to low pressure
C. Water is converted into ice
D. Both B. & C
Related Mcqs:
- Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is_______________?
A. Superheated vapour
B. Partially condensed vapour with quality of 0.9
C. Saturated vapour
D. Partially condensed vapour with quality of 0.1 - In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when_______________?
A. n = y = 1.4
B. n = 0
C. n = 1
D. n = 1.66 - Entropy change for an irreversible process taking system and surrounding together is___________________?
A. 0
B. > 0
C. < 0
D. None of these - For spontaneous changes in an isolated system (S = entropy) ___________________?
A. ds = 0
B. ds <0
C. ds > 0
D. ds = Constant - The absolute entropy for all crystalline substances at absolute zero temperature is ____________________?
A. Zero
B. Negative
C. More than zero
D. Indeterminate - A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the irreversible and reversible processes respectively) ?
A. Δ S1 is always Δ SR
C. Δ S1 is always > Δ SR
D. Δ S1 is always = Δ SR - “At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero”. This follows from the __________________?
A. Third law of thermodynamics
B. Second law of thermodynamics
C. Nernst heat theorem
D. Maxwell’s relations - At normal boiling point, molar entropy of vaporisation is _____________ Joule/K°.mole?
A. 72
B. 92
C. 142
D. 192 - Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of___________________?
A. Solution
B. Vaporisation
C. Formation
D. Sublimation - The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is_________________?
A. R loge 4
B. R log10 4
C. Cv log10 4
D. Cv loge 4
