Test on Fundamentals of Thermodynamics

Question 1: The work done during the expansion of a system against a constant external pressure is calculated using the formula w = ","p ex Δ V.

A. Yes

B. No

Explanation: The study materials state that "The work of expansion against a constant external pressure is : w = "," p ex Δ V ."

Question 2: Which of the following statements accurately describes an isobaric process according to the provided study materials?

A. The temperature of the system remains constant throughout the process.

B. The pressure of the system stays constant, meaning ΔP = 0.

C. The heat transferred to the system performs work and also alters the internal energy of the system.

D. The volume of the system remains constant during the process.

Explanation: According to the 'THERMODYNAMIC PROCESSES' section, an isobaric process is defined as 'a process in which the pressure of a system stays constant: ΔP = 0'. The materials also state that 'The heat transferred to the system does work, but also changes the internal energy of the system' during an isobaric process. Option 0 describes an isothermal process, and Option 3 describes an isochoric process.

Question 3: The provided study materials offer a specific example of an isolated system.

A. Yes

B. No

Explanation: The study materials define an isolated system and describe its wall characteristics, but the 'Example' field provided for the isolated system is blank, indicating no specific example was given.

Question 4: According to the provided study materials, which of the following expressions correctly represents the change in internal energy (∆U) of a system?

A. U f – U i

B. q + w

C. E total - E surroundings

D. - (U univ + U surroundings)

Explanation: The study materials define the change in internal energy as ∆U = U f – U i, where U f is the internal energy in the final state and U i is the internal energy in the initial state. Additionally, the First Law of Thermodynamics is mathematically expressed as ∆U = q + w, where q is heat and w is work. Both expressions are given as valid ways to represent ∆U.

Question 5: In a constant pressure calorimeter, the quantity measured is primarily the change in internal energy, U, of the system.

A. Yes

B. No

Explanation: The study materials state that for a constant pressure process, the heat flow (q) can be accounted for by measuring the enthalpy (H) of the system, and explicitly notes that H = q. Conversely, for a bomb calorimeter (constant volume), it is stated that what is measured is really the change in internal energy, U.