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Ch.19 - Chemical Thermodynamics
Chapter 19, Problem 18

(b) Without further information, can you conclude whether the amount of heat transferred to the system as it goes from state 1 to state 2 is the same or different compared to that upon going from state 2 back to state 1?

Verified step by step guidance
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Understand the concept of heat transfer in thermodynamics: Heat transfer is the process of energy moving from one system to another due to temperature difference. In thermodynamics, the amount of heat transferred depends on the path taken between two states.
Recognize that the problem involves a thermodynamic process between two states: State 1 and State 2. The question asks about the heat transfer when moving from State 1 to State 2 and then back from State 2 to State 1.
Recall that heat transfer is a path function, not a state function: Unlike state functions (such as internal energy, pressure, and volume), path functions depend on the specific process or path taken. Therefore, the heat transferred can vary depending on how the system transitions between states.
Consider the implications of path dependency: Without additional information about the specific processes or paths taken between State 1 and State 2, it is not possible to conclude whether the heat transferred is the same or different. Different paths can result in different amounts of heat transfer.
Conclude that more information is needed: To determine if the heat transferred is the same or different, details about the processes or paths taken between the states are necessary. This could include information about pressure, volume changes, or specific heat capacities involved in the transitions.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

First Law of Thermodynamics

The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another. In the context of heat transfer, this means that the total energy change in a system is equal to the heat added to the system minus the work done by the system. This principle is crucial for understanding how heat transfer relates to changes in a system's internal energy.
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First Law of Thermodynamics

Path Dependence of Heat Transfer

Heat transfer is path-dependent, meaning that the amount of heat exchanged between a system and its surroundings can vary based on the specific process or path taken. For example, the heat transferred during a reversible process may differ from that in an irreversible process, even if the initial and final states are the same. This concept is essential for analyzing thermodynamic cycles and understanding the differences in heat transfer between state changes.
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Heat Capacity

State Functions

State functions are properties of a system that depend only on its current state, not on the path taken to reach that state. Examples include internal energy, enthalpy, and pressure. In the context of the question, while the heat transferred may differ depending on the path, the change in internal energy between state 1 and state 2 is a state function, allowing us to analyze the system's energy changes without needing to know the specific heat transfer details.
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Related Practice
Textbook Question

Consider a process in which an ideal gas changes from state 1 to state 2 in such a way that its temperature changes from 300 K to 200 K. (a) Does the temperature change depend on whether the process is reversible or irreversible?

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Textbook Question

Consider a process in which an ideal gas changes from state 1 to state 2 in such a way that its temperature changes from 300 K to 200 K. (b) Is this process isothermal?

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Textbook Question

Consider a process in which an ideal gas changes from state 1 to state 2 in such a way that its temperature changes from 300 K to 200 K. (c) Does the change in the internal energy, ΔE, depend on the particular pathway taken to carry out this change of state?

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Textbook Question

A system goes from state 1 to state 2 and back to state 1. (c) Suppose the changes in state are reversible processes. Is the work done by the system upon going from state 1 to state 2 the same or different as compared to that upon going from state 2 back to state 1?

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Textbook Question
Consider a system consisting of an ice cube. (a) Under what conditions can the ice cube melt reversibly?
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Textbook Question

Indicate whether each statement is true or false. (a) ΔS is a state function. (b) If a system undergoes a reversible change, the entropy of the universe increases. (c) If a system undergoes a reversible process, the change in entropy of the system is exactly matched by an equal and opposite change in the entropy of the surroundings. (d) If a system undergoes a reversible process, the entropy change of the system must be zero.

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