- Physical Chemistry I
Spring 2012, Unique 52135
Lecture Summary, 13 April 2012
Rate Laws: The rate of a reaction, v(t),
is defined as the change in concentration of any of the species in
the reaction as a function of time:
v(t) = (-1/nu(Reactant))(d[Reactant]/dt) = (1/nu(Product))(d[Product]/dt).
Rate laws are constructed as v(t) = k[A]^m[B]^n...(etc) where m and m are unitless powers that take into account the order of each species in the reaction. Rate laws must be experimentally determined, they cannot be deduced from the stoichiometrically balanced reaction. The value of the rate law is always positive, and the rate constant, k, is an experimentally determined number with units necessary to make the units of v(t) mol/Ls.