MEGR 3161 Test 1 (2026) QUESTIONS WITH
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Section 1: Basic Concepts and Definitions
1. What is Thermodynamics?
A: The science of energy, its transformations, and its relationship to the properties of matter.
2. What is a System?
A: A quantity of matter or a region in space chosen for study.
3. Differentiate between a Closed System (Control Mass) and an Open System (Control
Volume).
A: A Closed System has fixed mass, and no mass crosses its boundary. Energy can cross.
An Open System has mass and energy that can cross its boundary.
4. What is an Isolated System?
A: A system where neither mass nor energy can cross the boundary.
5. Define a Property of a system.
A: Any characteristic of a system that can be measured without knowledge of the system's
history (e.g., pressure, temperature, volume).
6. Differentiate between Intensive and Extensive Properties.
A: Intensive properties are independent of the mass of the system (e.g., pressure, temperature,
density). Extensive properties are dependent on the mass of the system (e.g., total volume,
total energy, mass).
7. What is the State of a system?
A: The condition of a system as described by its properties.
8. Define a Process.
A: A change in the state of a system.
9. What is a Quasi-Equilibrium Process?
A: A process that occurs slowly enough that the system remains infinitesimally close to an
equilibrium state at all times.
10. What is the difference between the State Postulate and the Path of a process?
A: The State Postulate says the state of a simple, compressible system is completely specified by
,two independent, intensive properties. The Path is the series of states a system passes through
during a process.
11. What is a Cycle?
A: A process (or series of processes) that returns the system to its initial state.
12. Define Temperature.
A: A measure of the average kinetic energy of the molecules in a substance. It indicates the
direction of heat flow (from high to low temperature).
13. Define Pressure. What are its common units?
A: The normal force exerted by a fluid per unit area. Units: Pa (N/m²), kPa, bar, psi.
14. What is Absolute Pressure?
A: The actual pressure at a given point, measured relative to absolute zero pressure (a perfect
vacuum).
15. What is Gage Pressure?
A: The pressure relative to the local atmospheric pressure. 𝑃𝑔𝑎𝑔𝑒 = 𝑃𝑎𝑏𝑠 − 𝑃𝑎𝑡𝑚 .
16. What is Vacuum Pressure?
A: The pressure below atmospheric pressure. 𝑃𝑣𝑎𝑐 = 𝑃𝑎𝑡𝑚 − 𝑃𝑎𝑏𝑠 .
17. What is Energy? Name its two primary forms.
A: The capacity to cause change. The two primary forms are Macroscopic (KE, PE)
and Microscopic (Internal Energy, U).
18. Define Total Energy (E) of a system.
A: The sum of all forms of energy present in a system: 𝐸 = 𝑈 + 𝐾𝐸 + 𝑃𝐸.
19. What is Specific Heat?
A: The energy required to raise the temperature of a unit mass of a substance by one degree.
20. What is the Zeroth Law of Thermodynamics?
A: If two bodies are in thermal equilibrium with a third body, they are in thermal equilibrium
with each other. (This establishes temperature as a valid property).
Section 2: Energy, Work, and Heat
21. What is Work in a thermodynamic context?
A: A form of energy transfer between a system and its surroundings, driven by a force acting
through a displacement.
, 22. Work is a ______ function, meaning it depends on the path of the process.
A: Path.
23. What is the sign convention for work done BY the system?
A: Work done by the system is considered positive (𝑊 > 0).
24. What is the sign convention for work done ON the system?
A: Work done on the system is considered negative (𝑊 < 0).
25. What is Boundary Work (or P dV Work)?
A: The work associated with the expansion or compression of a fluid in a piston-cylinder device.
26. Write the integral equation for boundary work.
2
A: 𝑊𝑏 = ∫1 𝑃 𝑑𝑉
27. On a P-V diagram, what does the area under the process curve represent?
A: The boundary work for a quasi-equilibrium process.
28. For an Isobaric (constant pressure) process, what is the boundary work equation?
A: 𝑊𝑏 = 𝑃(𝑉2 − 𝑉1 )
29. What is Shaft Work?
A: The work transmitted by a rotating shaft, like in a turbine or compressor.
30. What is Spring Work?
1
A: The work done in compressing or extending a spring, 𝑊𝑠𝑝𝑟𝑖𝑛𝑔 = 2 𝑘(𝑥22 − 𝑥12 ).
31. Define Heat.
A: The form of energy transfer between two systems (or a system and its surroundings) due
solely to a temperature difference.
32. Heat is a ______ function, meaning it depends on the path of the process.
A: Path.
33. What is the sign convention for heat transfer TO the system?
A: Heat transfer to the system is considered positive (𝑄 > 0).
34. What is the sign convention for heat transfer FROM the system?
A: Heat transfer from the system is considered negative (𝑄 < 0).
35. What are the three modes of heat transfer?
A: Conduction, Convection, and Radiation.
VERIFIED CORRECT ANSWERS || 100%
GUARANTEED PASS <UPDATED VERSION>
Section 1: Basic Concepts and Definitions
1. What is Thermodynamics?
A: The science of energy, its transformations, and its relationship to the properties of matter.
2. What is a System?
A: A quantity of matter or a region in space chosen for study.
3. Differentiate between a Closed System (Control Mass) and an Open System (Control
Volume).
A: A Closed System has fixed mass, and no mass crosses its boundary. Energy can cross.
An Open System has mass and energy that can cross its boundary.
4. What is an Isolated System?
A: A system where neither mass nor energy can cross the boundary.
5. Define a Property of a system.
A: Any characteristic of a system that can be measured without knowledge of the system's
history (e.g., pressure, temperature, volume).
6. Differentiate between Intensive and Extensive Properties.
A: Intensive properties are independent of the mass of the system (e.g., pressure, temperature,
density). Extensive properties are dependent on the mass of the system (e.g., total volume,
total energy, mass).
7. What is the State of a system?
A: The condition of a system as described by its properties.
8. Define a Process.
A: A change in the state of a system.
9. What is a Quasi-Equilibrium Process?
A: A process that occurs slowly enough that the system remains infinitesimally close to an
equilibrium state at all times.
10. What is the difference between the State Postulate and the Path of a process?
A: The State Postulate says the state of a simple, compressible system is completely specified by
,two independent, intensive properties. The Path is the series of states a system passes through
during a process.
11. What is a Cycle?
A: A process (or series of processes) that returns the system to its initial state.
12. Define Temperature.
A: A measure of the average kinetic energy of the molecules in a substance. It indicates the
direction of heat flow (from high to low temperature).
13. Define Pressure. What are its common units?
A: The normal force exerted by a fluid per unit area. Units: Pa (N/m²), kPa, bar, psi.
14. What is Absolute Pressure?
A: The actual pressure at a given point, measured relative to absolute zero pressure (a perfect
vacuum).
15. What is Gage Pressure?
A: The pressure relative to the local atmospheric pressure. 𝑃𝑔𝑎𝑔𝑒 = 𝑃𝑎𝑏𝑠 − 𝑃𝑎𝑡𝑚 .
16. What is Vacuum Pressure?
A: The pressure below atmospheric pressure. 𝑃𝑣𝑎𝑐 = 𝑃𝑎𝑡𝑚 − 𝑃𝑎𝑏𝑠 .
17. What is Energy? Name its two primary forms.
A: The capacity to cause change. The two primary forms are Macroscopic (KE, PE)
and Microscopic (Internal Energy, U).
18. Define Total Energy (E) of a system.
A: The sum of all forms of energy present in a system: 𝐸 = 𝑈 + 𝐾𝐸 + 𝑃𝐸.
19. What is Specific Heat?
A: The energy required to raise the temperature of a unit mass of a substance by one degree.
20. What is the Zeroth Law of Thermodynamics?
A: If two bodies are in thermal equilibrium with a third body, they are in thermal equilibrium
with each other. (This establishes temperature as a valid property).
Section 2: Energy, Work, and Heat
21. What is Work in a thermodynamic context?
A: A form of energy transfer between a system and its surroundings, driven by a force acting
through a displacement.
, 22. Work is a ______ function, meaning it depends on the path of the process.
A: Path.
23. What is the sign convention for work done BY the system?
A: Work done by the system is considered positive (𝑊 > 0).
24. What is the sign convention for work done ON the system?
A: Work done on the system is considered negative (𝑊 < 0).
25. What is Boundary Work (or P dV Work)?
A: The work associated with the expansion or compression of a fluid in a piston-cylinder device.
26. Write the integral equation for boundary work.
2
A: 𝑊𝑏 = ∫1 𝑃 𝑑𝑉
27. On a P-V diagram, what does the area under the process curve represent?
A: The boundary work for a quasi-equilibrium process.
28. For an Isobaric (constant pressure) process, what is the boundary work equation?
A: 𝑊𝑏 = 𝑃(𝑉2 − 𝑉1 )
29. What is Shaft Work?
A: The work transmitted by a rotating shaft, like in a turbine or compressor.
30. What is Spring Work?
1
A: The work done in compressing or extending a spring, 𝑊𝑠𝑝𝑟𝑖𝑛𝑔 = 2 𝑘(𝑥22 − 𝑥12 ).
31. Define Heat.
A: The form of energy transfer between two systems (or a system and its surroundings) due
solely to a temperature difference.
32. Heat is a ______ function, meaning it depends on the path of the process.
A: Path.
33. What is the sign convention for heat transfer TO the system?
A: Heat transfer to the system is considered positive (𝑄 > 0).
34. What is the sign convention for heat transfer FROM the system?
A: Heat transfer from the system is considered negative (𝑄 < 0).
35. What are the three modes of heat transfer?
A: Conduction, Convection, and Radiation.
