Chapter 14

Chapter 14

1. Thermodynamics Basics

   • Transfer of energy between systems of particles
   • Conservation of Energy is key
   • Changes in energy affects its properties

2. Systems

   • Particles exchange energy via collisions
   • Systems can exchange energy with other systems
   • Example: Balloon filled with Oxygen molecules
   • Properties
     • Macroscopic
       • Temperature
       • Heat
       • When comparing 2 systems, macroscopic properties as a whole will be the same
     • Microscopic
       • position
       • velocity
       • When comparing 2 systems, they may not be the same on the microscopic level

3. Temperature

   • Associated with "hotness" and "coldness"
   • Energy is transferred from the "hotter" system to the "colder" system
     • Thermal equilibrium is reached when both systems have the same temperature
   • Conversions
     • Tk = Tc + 273.15
     • Tf = (9/5)Tc+32
     • Tc = 5/9 (Tf-32)
   • Scales
     • Farenheit
       • Water freezes at 32 degrees F
       • Water boils at 212 degrees F
     • Celsius
       • Water freezes at 0 degrees C
       • Water boils at 100 degrees C
     • Kelvin
       • Water freezes at 273.15 K
       • Water boils at 373.15 K
   • Lower limit is 0K, absolute zero

4. Heat/Heat Energy

   • Energy that flows between systems
   • Principle of Conservation of Energy
     • the amount of energy that "leaves" system 1 must be = to the amount of energy "entering" system 2
   • Transfer depends on temp difference
   • Units of Heat
     • SI unit = Joules
     • 1 calorie = 4.186 J
     • 1 Calorie = 1000 calories

5. Zeroth Law

   • If 2 systems (A & B) are in thermal equilibrium, and systems B & C are also in equilibrium, then A & C are in equilibrium
   • Temp is the only property of a system that will determine heat flow between it and another system