First Law - Closed Systems: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
Key points from this module:
  • The first law is an energy balance. For a closed system ΔU = Q + W.
  • Work is done when a gas expands against an external force in a piston-cylinder.
  • An adiabatic process takes place when the system is well insulated or takes place rapidly. 
From studying this module, you should now be able to:
  • Perform energy balances around a closed system.
  • Determine final states of various processes (e.g., constant pressure, adiabatic,constant volume, and constant temperature).
Prepared by John L. Falconer, Department of Chemical and Biological Engineering, University of Colorado Boulder