Table of Contents
By Danelle Hyland Department of chemistry Concordia College Moorhead, Minnesota
Introduction
Background Information State - The of state of a system is defined by specifying a minimum number in intensive variables. State Function - A function of the chosen independent variables that describes a property of the state (example V(T,P). Reversible processes - A process in which a system can be returned to its initial conditions along the same path, and every point along this path is an equilibrium state. Internal Energy(U) - All the energy of a system that is determined completely by the initial and final states of the system. Work(w) - The work done on or by a system that depends on the the initial and final states and on the path followed by the system between these states. Heat(q) - The transfer of energy across the boundary of a system that is due to a temperature difference between the system and its surroundings. It depends on the initial and final states and intermediate states of the system.
Different Forms of the First Law of Thermodynamics
Theory behind U = q + w
Theory behind U = q - PexdV The work(w) is equal to the negative external pressure times the change in volume (- PexdV), for systems where all the work is PV work. We know this is true because work is interchangeable in principle and in thermodynamics the changes in volume under a given pressure is accepted to be all work. Therefore the second form of the first law of thermodynamics is dU = dq - PexdV.
Theory behind U = TdS - PdV
U = TdS - PdV continued
Reversible and Irreversible Paths
Acknowledgements
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Author: djfiske
Email: dmhyland@cord.edu
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