# Ch 7 - Entropy

Here we present a discussion of the

#### Clausius Inequality

as it applies to reversible and irreversible processes. In this lesson, we define

#### entropy

, show how to obtain entropy data from the

#### NIST WebBook

and introduce an important new phase diagram: the

#### TS Diagram

. We show how and why the TS Diagram is particularly useful for the analysis of

#### thermodynamic cycles

. We use the

#### Clausius Inequality

and the definition of

#### entropy

to set the stage for the introduction of

#### entropy generation

. We show that the area under an irreversible process path on a TS Diagram is not equal to the heat transferred during the process. We conclude by showing that the

is true: The

#### entropy of the universe

cannot decrease. In this lesson, we derive the

#### 1st and 2nd Gibbs Equations

. We show how they can be used to evaluate for processes involving incompressible substances and ideal gases. In this lesson, we introduce

and

#### relative pressure

. Then we discuss

#### isentropic

processes on ideal gases in which the heat capacities are constant. This turns out to be a special case of the more general

#### polytropic process

. We then show how to calculate the boundary work for polytropic processes in closed systems. We conclude by showing that

#### an isentropic compression

of an ideal gas requires the least work. - The Clausius Inequality
- Entropy: A New Property
- The Principle of Increasing Entropy
- Fundamental Property Relationships
- Polytropic and Isentropic Processes • The lessons in Chapter 7 are listed below
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