Units, of rate constants

By custom, the units of concentration are always included in the units of rate constants but are customarily omitted for equilibrium constants. Problem 7-15 provides further insights. 

The units of rate constant for a first order reaction from equation (1.21) is measured as (time)-1 and can be represented as sec-1, min-1 or hour-1. 

Units of rate constant is (cone.) 2 (time)1 or generally mol-2 lit2sec 1 or mol2 dm6 sec-1. 

Because the general form of the units of rate constants is (time) (concentration)1 , the unit of the rate constant of a zero-order reaction is (time) 1(con-centration)1. The rate of zero-order reaction is independent of the concentration of the reactant, which is often encountered in heterogeneous reactions on the surface such as activated carbon adsorption. 

Overall reaction order Units of rate constant k Method to determine /cfor rate laws with one reactant... 

Rate constant is a measure of the intrinsic rate of a reaction. The unit of rate constant is sec-1. 

The units of rate constant for a given reaction can be determined by starting with the appropriate rate equation for the reaction, as is shown in the following examples. 

Order Rate equation Differentiai form Integrated form Units of rate constant Half-life... 

Overall reaction Units of rate constant Method to determine /r for rate... 

Units of rate = (units of rate constant) (units of concentration) ... 

According to the reaction stoichiometry 1 2 reactant products, the gas will expand. Since the unit of rate constant is per second, we have a first-order reaction (irreversible). Therefore, the rate will be ... 

The reactant CsHg A) is the limiting one and even in gas phase there is no volume variation, sa=0 A + BR + S). Based on the unit of rate constant, we have a... 

HzQ = hydroquinone. Third-order rate law incorporating [HO"l term. Value of 13.4 may be obtained depending on mechanistic interpretation. < Units of rate constant are mol 1- s since a term in [H+J is involved. 

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