1: Applying Models to Thermal Phenomena
- Page ID
- 104082
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)In this chapter we introduce the Energy-Interaction Model, which is the primary focus of this course. We will apply this model together with the Three-Phase Model of Pure Substances in order to understand various physical phenomena. We will analyze pure substances going through temperature and phase changes and chemical reactions.
- 1.1: Where are we Headed?
- The Energy-Interaction Model tells us what is energy, how it is conserved, and how it is transferred. We will see that by applying the Energy-Interaction Model to seemingly very strange thermal phenomena, we can make sense of them, we can explain what is going on, and we can answer all kinds of questions about the phenomena. In this Chapter we will apply Energy-Interaction Model to substances going through temperature changes or phase changes and to several chemical reactions.
- 1.2: Three-Phase Model of Pure Substances
- We start our analysis of energy by studying what role it plays in the three-phases of matter: solids, liquids, and gases. We will first provide a brief overview of the three phases of matter and explain which properties of a substance change when energy is either added or removed from the substance. Specifically, we will graphically depict how the temperature of a substance changes as energy is being added or removed from the substance.
- 1.3: Energy-Interaction Model
- We introduce the Energy-Interaction Model, emphasizing energy conservation and energy as a universal, abstract concept. We discuss how changes—not absolute values—reflect interactions, with heat and work as primary transfer forms. Through examples, we explain closed and open systems and time intervals in analysis. Concepts like specific heat, thermal energy, and bond energy describe changes in thermal and chemical processes, setting up a detailed atomic-level perspective in later chapters.
- 1.4: Working With the Energy-Interaction Model
- We apply the Energy-Interaction and Three-Phase Models to understand pure substances and chemical reactions, using Energy-Interaction Diagrams to track energy changes in closed and open systems. These diagrams outline initial and final states for systematic analysis. Examples like mixing substances and heating water show energy transfers, and ATP hydrolysis illustrates bond energy changes related to energy release or absorption.
- 1.5: Units, Data Tables, and Equations
- This section provides essential reference material, including common units for energy and power in SI units, a thermal data table with melting and boiling points, heats of melting and vaporization, and specific heats for various substances, along with key energy equations. It covers internal energies (thermal and bond) and mechanical energies (kinetic and potential), with indicators showing each energy’s dependence on specific physical parameters.
- 1.6: Looking Ahead
- Let’s reflect on what we have done in the course up to this point. Our focus has been on developing an energy model, which we have called the Energy-Interaction Model, and on understanding how to apply it to some particular thermal phenomena. We have used this model to begin to understand some of the more general thermal properties of matter. We will continue to develop the Energy-Interaction Model as we apply it to new kinds of phenomena in Chapter 2.