Chemistry 2214A/B Lecture Notes - Lecture 5: Isothermal Process, Boltzmann Distribution, Thermodynamics
22 Jan 2015
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Document Summary
The internal energy is the total thermal energy of a system of interest. When the system undergoes a change of state, the change of internal energy is represented as: u = ufinal - uinitial. The thermal energy of an ideal gas is its average kinetic energy, . In this case, u depends only on temperature. U = = (3/2) rt for one mole. Molecules can exist in states with energy 0, 1, . For a given number of molecules, the relative population of molecules in any two given states can be described by the boltzmann distribution. In the equation, n2 and n1 are the number of molecules in state 2 and 1 with energy e2 and e1 respectively. T is the parameter that characterizes the distribution. A low temperature implies that only low-energy states are occupied; a high temperature indicates that high-energy states are also occupied. Zero temperature (t = 0) indicates that only the ground state is occupied.
