Reaction Mechanisms
Reaction Mechanisms Most reactions occur in a series of elementary steps These steps together are called the reaction mechanism Molecules that form in one step and are consumed in the next are called reaction intermediates
2N2O(g) 2N2(g) + O2(g) Step 1: Step 2: (slow) (fast) Reaction Mechanism Step 1: Step 2: (slow) (fast) 2N2O(g) 2N2(g) + O2(g) Intermediate
Rate-Determining Step Each elementary step has its own rate The overall rate of a reaction is determined by the rate of the slowest step, the rate-determining step (RDS) Therefore, the rate law for the rate-determining will be the rate law for the overall reaction The molar coefficients in the RDS will be the exponents in the overall rate law
Overall rate law depends on the RDS. Reaction Mechanism Step 1: Step 2: (slow) (fast) 2N2O(g) 2N2(g) + O2(g) Intermediate Overall rate law depends on the RDS. Molar coefficients of RDS will be the exponents. r = k[N2O]
Practice P. 390 #2 P. 391 #1,2,3abcd Worksheets