Thermodynamics Short questions and Answers.
1. Thermodynamics is the branch of physics that
deals with the study of energy and its transformations in systems.
2. It encompasses the principles governing heat, work,
temperature, and energy transfer.
3. The laws of thermodynamics provide a framework for
understanding the behavior of macroscopic systems.
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4. The first law of thermodynamics states that energy
is conserved in a closed system.
5. It relates the change in internal energy of a system
to the heat added to it and the work done on or by the system.
6. The second law of thermodynamics establishes the
concept of entropy, which characterizes the direction of spontaneous processes.
7. It states that the entropy of an isolated system
tends to increase over time.
8. The third law of thermodynamics states that the
entropy of a perfect crystal approaches zero as its temperature approaches
absolute zero.
9. The concept of temperature is a measure of the
average kinetic energy of the particles in a system.
10. The
Kelvin scale is an absolute temperature scale with zero Kelvin (0 K)
corresponding to absolute zero (-273.15°C or -459.67°F).
11. Heat is
the transfer of energy between two systems due to a temperature difference.
12.
It can
be transferred by conduction, convection, or radiation.
13. Work is
the transfer of energy due to a force acting through a distance.
14.
It can
be mechanical, electrical, or other forms of work.
15. Thermodynamic
systems can be classified as open, closed, or isolated systems based on the
exchange of matter and energy with their surroundings.
16.
A closed
system allows the transfer of energy but not matter across its boundaries.
17.
An open
system allows both energy and matter transfer.
18. An
isolated system does not exchange energy or matter with its surroundings.
19.
The
state of a thermodynamic system is described by its properties, such as
temperature, pressure, volume, and composition.
20.
The
equation of state relates the state variables of a system.
21. The
ideal gas law is an equation of state that describes the relationship between
pressure, volume, temperature, and the number of moles of an ideal gas.
22. Enthalpy
(H) is a thermodynamic property that combines the internal energy of a system
with the pressure-volume work.
23. Entropy
(S) is a measure of the disorder or randomness of a system.
24. Gibbs
free energy (G) combines the enthalpy and entropy to determine the spontaneity
of a process.
25. Heat
capacity is the amount of heat required to raise the temperature of a substance
by one degree.
26. Specific
heat capacity is the heat capacity per unit mass of a substance.
27. The
concept of phase transitions describes the change of a substance from one state
(solid, liquid, or gas) to another.
28. The heat
of fusion is the amount of heat required to change a substance from a solid to
a liquid state at its melting point.
29. The heat
of vaporization is the amount of heat required to change a substance from a
liquid to a gas state at its boiling point.
30. The
Carnot cycle is a theoretical cycle of an ideal heat engine that operates
between two temperatures.
31. It sets
the upper limit of efficiency for any heat engine operating between the same
two temperatures.
32.
Thermal
efficiency is the ratio of the work output to the heat input in a heat engine.
33. The
concept of reversibility describes a process that can be reversed without any
change in entropy.
34. Real
processes are typically irreversible due to factors like friction, heat
transfer through finite temperature differences, and irreversibilities within
the system.
35. The
concept of heat engines, refrigerators, and heat pumps are based on the
principles of thermodynamics.
36. Heat
engines convert heat energy into mechanical work.
37. Refrigerators
and heat pumps transfer heat from a low-temperature region to a
high-temperature region.
38. The
coefficient of performance (COP) is used to measure the effectiveness of refrigerators
and heat pumps.
39. The
concept of entropy generation describes the irreversible processes that lead to
an increase in the entropy of the universe.
40. The
concept of thermodynamic equilibrium refers to a state where there is no net
transfer of heat or energy between systems.
41. Phase
diagrams depict the relationships between temperature, pressure, and the phases
of a substance.
42. Critical
points on phase diagrams mark the conditions where the liquid and gas phases
become indistinguishable.
43. The
concept of fugacity describes the escaping tendency of molecules from a
non-ideal gas or liquid.
44. The Van
der Waals equation of state is a modification of the ideal gas law to account
for the intermolecular forces and volume occupied by gas molecules.
45. The
concept of chemical potential describes the tendency of molecules to move
between phases or react.
46. Gibbs-Duhem
equation relates the changes in chemical potential, pressure, and temperature
for multicomponent systems.
47. The
Maxwell relations are a set of equations that connect partial derivatives of
thermodynamic properties.
48. The
concept of heat transfer coefficient quantifies the rate of heat transfer
between a solid surface and a fluid.
49.
The
Stefan-Boltzmann law describes the relationship between the temperature and the
radiant energy emitted by a black body.
50. The
concept of black body radiation led to the development of quantum mechanics.
51. The
concept of entropy production relates to the irreversibility of processes and
the increase in entropy.
52.
The
Clausius inequality states that the integral of the entropy production in a
cycle is greater than or equal to zero.
53. The
concept of thermodynamic potentials, such as internal energy, Helmholtz free
energy, and Gibbs free energy, allows the determination of the most stable
state of a system.
54. The
concept of chemical equilibrium describes a state where the rates of forward
and reverse reactions are equal, and there is no net change in the
concentration of reactants and products.
55. The
equilibrium constant (K) is a thermodynamic quantity that relates the
concentrations of reactants and products in a chemical equilibrium.
56. Le
Chatelier's principle predicts the effect of changes in temperature, pressure,
and concentration on the equilibrium position of a reaction.
57. The
concept of activity describes the effective concentration of a species in a
mixture, accounting for the interactions between molecules.
58. The
concept of phase rule relates the number of phases, components, and degrees of
freedom in a system.
59. The
concept of enthalpy of reaction quantifies the heat evolved or absorbed in a
chemical reaction.
60. Hess's
law states that the enthalpy change of a reaction is independent of the
reaction pathway and depends only on the initial and final states.
61. The
concept of standard conditions defines a set of reference conditions (usually
298 K and 1 atm) for the calculation of standard enthalpy, entropy, and Gibbs
free energy changes.
62. The
Nernst equation relates the potential of an electrochemical cell to the
activities of the species involved.
63. The
concept of heat exchangers allows efficient transfer of heat between two fluids
at different temperatures.
64. The
Clausius-Clapeyron equation relates the vapor pressure of a substance with
temperature and enthalpy of vaporization.
65. The
concept of exergy quantifies the maximum useful work that can be obtained from
a system in equilibrium with its surroundings.
66. The
Maxwell-Boltzmann distribution describes the distribution of molecular speeds
in a gas at a given temperature.
67. The
concept of critical phenomena refers to the behavior of a substance near its
critical point, where its properties change dramatically.
68. The
concept of adiabatic processes describes a process in which no heat transfer
occurs between a system and its surroundings.
69. The
concept of polytropic processes describes processes with variable heat and work
transfer.
70. The
concept of steady-state describes a system in which the properties remain
constant with time despite energy transfer.
71. The
concept of specific heat capacity ratio relates the heat capacities at constant
pressure and constant volume for a gas.
72. The
concept of absolute zero is the lowest possible temperature, where molecular
motion ceases.
73. The
concept of calorimetry allows the measurement of heat transfer during a process
or reaction.
74. The
concept of internal combustion engines involves the combustion of a fuel-air
mixture to produce mechanical work.
75. The
concept of thermal expansion describes the increase in size or volume of a
substance with temperature.
76. The
concept of heat pumps and air conditioning involves the transfer of heat from a
low-temperature region to a high-temperature region using mechanical work.
77. The
concept of entropy change in a process determines the maximum possible
efficiency of a heat engine.
78. The
concept of enthalpy change in a reaction determines the heat evolved or
absorbed during a chemical reaction.
79. The
concept of heat transfer through conduction involves the transfer of heat
through direct molecular interaction.
80. The
concept of heat transfer through convection involves the transfer of heat
through the movement of fluid particles.
81. The
concept of heat transfer through radiation involves the transfer of heat
through electromagnetic waves.
82. The
concept of specific entropy relates the entropy change to the mass or mole of a
substance.
83. The
concept of adiabatic walls describes a system where no heat is allowed to
transfer across the boundaries.
84. The
concept of reversible processes describes idealized processes that can be
reversed without any irreversibilities.
85. The
concept of entropy change in an adiabatic process is zero.
86. The
concept of thermodynamic cycles involves a series of processes that return a
system to its original state.
87. The
concept of Carnot efficiency represents the maximum possible efficiency of a
heat engine operating between two temperatures.
88. The
concept of chemical potential energy relates to the energy stored in chemical
bonds and the potential for chemical reactions.
89. The
concept of specific heat capacity at constant pressure (Cp) and constant volume
(Cv) characterizes the heat capacity of a substance.
90. The
concept of spontaneous processes describes processes that occur without any
external intervention.
91. The
concept of thermodynamic stability refers to the tendency of a system to reach
equilibrium.
92. The
concept of work done by or on a system is determined by the product of force
and displacement.
93. The
concept of thermodynamic efficiency relates the useful work output to the total
energy input.
94. The
concept of entropy generation relates to the irreversible processes and the
increase in total entropy in a system.
95. The
concept of enthalpy change in phase transitions characterizes the heat absorbed
or released during the transition.
96. The
concept of specific heat capacity at constant pressure (Cp) and constant volume
(Cv) depends on the molecular structure and degrees of freedom.
97. The
concept of heat transfer coefficient relates the rate of heat transfer to the
temperature difference and properties of the medium.
98. The
concept of thermodynamic equilibrium describes a state where there is no net
change in any property of a system.
99. The
concept of heat engines follows the principles of thermodynamics to convert
heat energy into useful work.
The concept of thermal conductivity characterizes the ability of a material to conduct heat.