Lab 10 Thermodynamics PHY250L
STRAIGHTLINE INTRODUCTION TO
PHYSICS (LAB) PHY250L LAB 10
THERMODYNAMICS COMPLETE STUDY
GUIDE QUESTIONS WITH ANSWERS
AND EXPLANATION LATEST GUIDE
2025/2026.
,Lab 10 Thermodynamics PHY250L
Student Name: TUTOR2025
Access Code (located on the underside of the lid of your lab kit): [Kit2251]
Lab Report Format Expectations
Utilize college level grammar and formaṄng when answering text based questions.
Report all equations in a proper mathematical format, with the correct signs and symbols.
Submissions with incomplete or improperly formatted responses may be rejected.
Pre-Lab Questions
1. The first law of thermodynamics discusses the interplay between heat and work and how they
come together to describe the internal energy changes of a system undergoing a
thermodynamic process. Importantly, though, the first law of thermodynamics is, at its core, a
statement about the conservation of energy. Energy cannot be created or destroyed. it cannot
vanish into nothingness or spontaneously appear. This law can be stated mathematically as:
ΔU =Q−W
Explain how this equation demonstrates both the first law of thermodynamics∧the concept of conservatio
CORRECT ANSWER
According to the equation, a system's change in internal energy is equal to the net heat transfer
into the system less the net work the system does. This indicates that heat may be added to or
removed from a system, as well as work done on or by the system, to alter its internal
energy.Furthermore, energy cannot be generated or destroyed, according to the equation. This
is so because both the system's net work and the net heat transfer into the system are energy-
producing processes. The total quantity of energy in a system must be constant if the change in
internal energy of the system is equal to the net heat transfer into the system less the net work
done by the system.
2. Note the negative (-) sign for work, W, in the above equation. The choice of a negative or a
positive sign depends on the way you describe the system.
Explain when the work term would have a positive magnitude and when it would have a
negative magnitude. In your response, utilize the work equation, which is below, to justify your
response.
W =−Pext x ΔV
CORRECT ANSWER
The direction of the work being done determines the sign of the work component, W, in the
, Lab 10 Thermodynamics PHY250L
equation W = -PΔV. Positive Magnitude (W > 0): When the system makes an impact on its
surroundings, it is said to be working. This usually happens when the system's volume is
decreased (ΔV < 0) or when it is compressed. Consequently, ΔV is negative, and a
positive work term is obtained by multiplying a negative value by a negative pressure (-P).
Negative Magnitude (W < 0): When the environment exerts work on the system, the work is
negative. This often occurs as the system grows, increasing volume (ΔV > 0). A negative work
term is obtained by multiplying a positive value by a negative pressure (-P).
3. The second law of thermodynamics states that the entropy of an isolated system can never
decrease over time, and is constant if and only if all processes are reversible. Isolated systems
spontaneously evolve towards thermodynamic equilibrium—the state of maximum entropy of
the system. More simply put: the entropy of the universe (the ultimate isolated system) only
increases and never decreases.
Explain, using probability theory and the concepts of macrostates and microstates, why entropy
increases. Be specific and state your response with enough detail that your level of
understanding is clearly demonstrated.
CORRECT ANSWER
Microstates: These are all potential configurations of a system's particles at the tiny level. Every
microstate has a different arrangement. Macrostates: These stand for a system's macroscopic
characteristics, such as volume, pressure, and temperature. There are several microstates that
can match a macrostate. Probability and Entropy: The number of alternative microstates (W)
that correspond to a particular macrostate is measured by entropy (S). The underlying idea is
that systems naturally gravitate toward states with the highest number of reachable
microstates. Imagine a system that is isolated. The system may be in one of several connected
microstates and a certain macrostate at any one time. The number of microstates for a
particular macrostate has a direct bearing on entropy. There are more microstates at higher
entropy. Since there are fewer possibilities to organize the particles for that macrostate, the
system may start out in a low-entropy state. Particles travel and interact across time, exploring
different microstates. The system is statistically significantly more likely to transition into higher
entropy states because of the sheer amount of microstates that exist for a high-entropy state.
The probability of particles self-organizing into a lower-entropy state is quite minimal, as there
are many fewer methods to obtain that particular configuration.
4. When you put a few drops of food coloring in water, the molecules of food coloring will
eventually diffuse throughout the whole glass. Use the Second Law of Thermodynamics to
explain why the entropy of the diffused food coloring is greater than when you initially drop the
STRAIGHTLINE INTRODUCTION TO
PHYSICS (LAB) PHY250L LAB 10
THERMODYNAMICS COMPLETE STUDY
GUIDE QUESTIONS WITH ANSWERS
AND EXPLANATION LATEST GUIDE
2025/2026.
,Lab 10 Thermodynamics PHY250L
Student Name: TUTOR2025
Access Code (located on the underside of the lid of your lab kit): [Kit2251]
Lab Report Format Expectations
Utilize college level grammar and formaṄng when answering text based questions.
Report all equations in a proper mathematical format, with the correct signs and symbols.
Submissions with incomplete or improperly formatted responses may be rejected.
Pre-Lab Questions
1. The first law of thermodynamics discusses the interplay between heat and work and how they
come together to describe the internal energy changes of a system undergoing a
thermodynamic process. Importantly, though, the first law of thermodynamics is, at its core, a
statement about the conservation of energy. Energy cannot be created or destroyed. it cannot
vanish into nothingness or spontaneously appear. This law can be stated mathematically as:
ΔU =Q−W
Explain how this equation demonstrates both the first law of thermodynamics∧the concept of conservatio
CORRECT ANSWER
According to the equation, a system's change in internal energy is equal to the net heat transfer
into the system less the net work the system does. This indicates that heat may be added to or
removed from a system, as well as work done on or by the system, to alter its internal
energy.Furthermore, energy cannot be generated or destroyed, according to the equation. This
is so because both the system's net work and the net heat transfer into the system are energy-
producing processes. The total quantity of energy in a system must be constant if the change in
internal energy of the system is equal to the net heat transfer into the system less the net work
done by the system.
2. Note the negative (-) sign for work, W, in the above equation. The choice of a negative or a
positive sign depends on the way you describe the system.
Explain when the work term would have a positive magnitude and when it would have a
negative magnitude. In your response, utilize the work equation, which is below, to justify your
response.
W =−Pext x ΔV
CORRECT ANSWER
The direction of the work being done determines the sign of the work component, W, in the
, Lab 10 Thermodynamics PHY250L
equation W = -PΔV. Positive Magnitude (W > 0): When the system makes an impact on its
surroundings, it is said to be working. This usually happens when the system's volume is
decreased (ΔV < 0) or when it is compressed. Consequently, ΔV is negative, and a
positive work term is obtained by multiplying a negative value by a negative pressure (-P).
Negative Magnitude (W < 0): When the environment exerts work on the system, the work is
negative. This often occurs as the system grows, increasing volume (ΔV > 0). A negative work
term is obtained by multiplying a positive value by a negative pressure (-P).
3. The second law of thermodynamics states that the entropy of an isolated system can never
decrease over time, and is constant if and only if all processes are reversible. Isolated systems
spontaneously evolve towards thermodynamic equilibrium—the state of maximum entropy of
the system. More simply put: the entropy of the universe (the ultimate isolated system) only
increases and never decreases.
Explain, using probability theory and the concepts of macrostates and microstates, why entropy
increases. Be specific and state your response with enough detail that your level of
understanding is clearly demonstrated.
CORRECT ANSWER
Microstates: These are all potential configurations of a system's particles at the tiny level. Every
microstate has a different arrangement. Macrostates: These stand for a system's macroscopic
characteristics, such as volume, pressure, and temperature. There are several microstates that
can match a macrostate. Probability and Entropy: The number of alternative microstates (W)
that correspond to a particular macrostate is measured by entropy (S). The underlying idea is
that systems naturally gravitate toward states with the highest number of reachable
microstates. Imagine a system that is isolated. The system may be in one of several connected
microstates and a certain macrostate at any one time. The number of microstates for a
particular macrostate has a direct bearing on entropy. There are more microstates at higher
entropy. Since there are fewer possibilities to organize the particles for that macrostate, the
system may start out in a low-entropy state. Particles travel and interact across time, exploring
different microstates. The system is statistically significantly more likely to transition into higher
entropy states because of the sheer amount of microstates that exist for a high-entropy state.
The probability of particles self-organizing into a lower-entropy state is quite minimal, as there
are many fewer methods to obtain that particular configuration.
4. When you put a few drops of food coloring in water, the molecules of food coloring will
eventually diffuse throughout the whole glass. Use the Second Law of Thermodynamics to
explain why the entropy of the diffused food coloring is greater than when you initially drop the
