# Chapter 2: Systems and Their Properties

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$$\newcommand{\A}{_{\text{A}}} % subscript A for solvent or state A$$
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$$\newcommand{\C}{_{\text{C}}} % subscript C$$
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$$\newcommand{\cbB}{_{c,\text{B}}} % c basis, B$$
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$$\newcommand{\kHi}{k_{\text{H},i}} % Henry's law constant, x basis, i$$
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$$\newcommand{\sys}{\subs{sys}} % system property$$
$$\newcommand{\sur}{\sups{sur}} % surroundings$$
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$$\newcommand{\cm}{\subs{cm}} % center of mass$$
$$\newcommand{\rev}{\subs{rev}} % reversible$$
$$\newcommand{\irr}{\subs{irr}} % irreversible$$
$$\newcommand{\fric}{\subs{fric}} % friction$$
$$\newcommand{\diss}{\subs{diss}} % dissipation$$
$$\newcommand{\el}{\subs{el}} % electrical$$
$$\newcommand{\cell}{\subs{cell}} % cell$$
$$\newcommand{\As}{A\subs{s}} % surface area$$
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$$\newcommand{\dq}{\dBar q} % heat differential$$
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$$\newcommand{\fug}{f} % fugacity$$
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$$\newcommand{\G}{\varGamma} % activity coefficient of a reference state (pressure factor)$$
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$$\newcommand{\Ej}{E\subs{j}} % liquid junction potential$$
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This chapter begins by explaining some basic terminology of thermodynamics. It discusses macroscopic properties of matter in general and properties distinguishing different physical states of matter in particular. Virial equations of state of a pure gas are introduced. The chapter goes on to discuss some basic macroscopic properties and their measurement. Finally, several important concepts needed in later chapters are described: thermodynamic states and state functions, independent and dependent variables, processes, and internal energy.