ABSTRACT
In chemically reactive systems the total number of moles may change, but the total mass is conserved" Becausee p1 = multiplying Eq. M1 gives
dp· -
1 = M·ot·r-dt J J d ln V = M ot r _ 0 d ln V
dt ./ ) I} dt (5.62)
The rate of change of mass fraction g1 becomes
dg1 _ d(p1/ p) _ 1 dp1 p1 dp _ Mp1r (din V dlnp\ - --- ----- ---g. __ _L __ I dt - dt - p df p2 dt - P j dt I dt } (5.63)
dt dt (5.64)
so Eq. (5.63) becomes dg1 Mpf dt p (5.65)
In this formulation, r" is the intensive reaction rate per unit mass of the system. Because the total mass m of the reacting system is conserved,
r" = R* =!!__(X) = d~" = !_ (5.66) m dt m dt p
Calculation of concentration changes as described in this section requires the chemical waction rate in terms of composition as well as the temperature and pressure of the reacting system. These reaction rate expressions have to be developed from the interpretation of experimental data collected for the reaction rate measurements.
