CHEM 121 Lecture Notes - Lecture 16: Heat Capacity, Joule, Ideal Gas
13 Jul 2015
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Chem121 - lecture 16 - characteristics of enthalpy change and hess"s law. A piece of silver of mass 362g has a specific heat capacity of 85. 7 j/oc. Heat capacity of a gas is greatest when gas is diatomic and pressure is constant. Ideal gas: cv = (3/2)r, cp = (5/2)r. Particles get ( )r from every translational degree of freedom plus some. Intensive vs. extensive properties extra from bond degree freedom. Intensive: properties that are independent of the amount of matter being observed. Extensive: properties that depend on the quantity of matter. Be careful using stoichiometry with extensive properties, particularly with number of moles. Characteristics of enthalpy change: h depends on quantity of matter (extensive) H = 180. 50 kj formation of 4 moles of no(g) would require 2(180. 50) kj = 361. 00 kj formation of 1 mole of no(g) would require ( )(180. 50) kj = 90. 25 kj/mol. H changes sign when a process is reversed.
