chem1 virtual textbook

a reference text for General Chemistry

Stephen Lower

Simon Fraser University

The pages in this section of the Chem1 Virtual Textbook offer a thorough introduction to thermodynamics at the first-year university level. The Second Law and its applications to chemical equilibrium are covered in a separate lesson set.

All chemical changes are accompanied by the absorption or release of heat. The intimate connection between matter and energy has been a source of wonder and speculation from the most primitive times; it is no accident that fire was considered one of the four basic elements (along with earth, air, and water) as early as the fifth century BCE.

In this unit we will review some of the fundamental concepts of energy and heat and the relation between them. We will begin the study of thermodynamics, which treats the energetic aspects of change in general, and we will finally apply this specifically to chemical change. Our purpose will be to provide you with the tools to predict the energy changes associated with chemical processes. This will build the groundwork for a more ambitious goal: to predict the direction and extent of change itself.

One of the interesting things about thermodynamics is that although it deals with matter, it makes no assumptions about the microscopic nature of that matter. Thermodynamics deals with matter in a macroscopic sense; it would be valid even if the atomic theory of matter were wrong. This is an important quality, because it means that reasoning based on thermodynamics is unlikely to require alteration as new facts about atomic structure and atomic interactions come to light.

> To access the desired page, click one of the six
> lesson titles immediately below; you can also go directly to any sub-section within a lesson by clicking on a smaller heading.

1- Energy, heat and work in Chemistry

Basic stuff you need to know

- Energy: what is it?
- Kinetic and potential energy
- "Chemical energy" and thermal energy
- Energy scales and units
- Heat and work: are they energy or what?
- Concept map

2- The First Law of Thermodynamics

One of the most fundamental laws of nature, and how we can use it

- A thermodynamic view of the world
- Internal energy and the First Law
- Pressure-volume work
- Reversible Processes
- The enthalpy
- Heat capacity and specific heat
- Concept Map

3- Molecules as energy carriers and converters

How molecules exchange and transport thermal and kinetic energy

- Chemical energy: potential + kinetic
- How molecules take up thermal energy
- Enthalpy and standard enthalpy change
- Enthalpy increases with temperature
- Concept Map

4- Thermochemistry and calorimetry

How enthalpy changes are measured and predicted

- Thermochemical equations and standard states
- Enthalpy of formation
- Hess' Law and thermochemical calculations
- Calorimetry: measuring ΔH in the laboratory
- Concept Map

5- Some applications of enthalpy and the First Law

Finally, why this stuff is worth learning!

- Enthalpy diagrams
- Bond enthalpies and bond energies
- Energy content of fuels
- Energy content of foods
- Thermodynamics and the weather
- Concept Map

More on-line resources

Energy, Enthalpy and the First Law of Thermodynamics (Purdue Univ.)

videos - The following university-level lectures cover much of the material relevant to energetics and the first law, but parts extend into more advanced topics of thermodynamics.

Introduction to thermodynamics MIT 5.60a; State of a system, 0th law, equation of state (49 min) (See the course home page)

YaleCourses Physics 200: Introduction to thermodynamics (72 min)
Temperature, heat and the First Law (75 min)