Biochemistry 4115: Thermodynamics Part 1 Lecture Notes

Biochemistry 4115: Thermodynamics Part 1 Lecture Notes

Course Information

  • Instructor: Dr. Daniel J. Slade (dslade@vt.edu)

  • Lecture: 5 – Thermodynamics Part 1

  • Date: September 3rd, 2025

  • Class Schedule: Monday, Wednesday, Friday 11:15 AM – 12:05 PM

  • Teaching Assistant-Led Section: Wednesday 5:30 PM – 6:20 PM

Introduction to Thermodynamics

  • Definition (Oxford Dictionary): The branch of physical science that deals with the relations between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and, by extension, of the relationships between all forms of energy.

  • Relevance: All chemical, physical, and biological processes are governed by three fundamental principles—the laws of thermodynamics.

The Laws of Thermodynamics

  • 1st Law of Thermodynamics: The total energy of an isolated system is conserved.

  • 2nd Law of Thermodynamics: Systems proceed from ordered, low-entropy states to disordered, high-entropy states.

    • Implication for Biology: Every energy transfer or transformation increases the entropy of the universe.

  • 3rd Law of Thermodynamics: The entropy of any crystalline, perfectly ordered substance is exactly zero at 0K0K temperature.

Basic Concepts: Systems in Thermodynamics

  • Definition of a System: In thermodynamics, the