T-L02 Phase Changes and Ideal Gas Law


Pre-Amble

  1. Test Results (if ready)

State Variables:

Atoms and Moles

Basic phases of matter and phase diagrams

Phase diagram

Ideal Gas Law & Processes

A Macroscopic Description of Matter(Slides)


FAQ

  1. Why are the the quantities such are R and NA not simple numbers? ANS: This is due to history and the way units were first defined. For example, we could define a new unit of temperature the [bai]. If 10 [bai] = 8.31 [K] then R=10. (Water would freeze at 328.7 bai, and boil at 448 bai. I could then define a scale for daily use T [xiaobai] = T[bai] -328.7 so that the freezing point of water would be 0 [xiaobai] and boiling point would be 1nt06.5 [xiaobai] ) Similarily we could define a new unit of mass, the [white] such that so that Avrogadro's number is 1024!
  2. Why can we only consider quasi-static processes in thermodynamics? ANS: P,V and T are only defined for thermodynamic equilibrium. if things move fast we leave this equilibrium and the state variables are defined. i.e. T is not constant in the system, P is not constant. To draw a path on the pV diagram we need to go slow. See Quasistatic and Reversible Processes (Khan Academy)

States of Matter
States of Matter
Gas Properties
Ideal Gases

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