Manipulation of experimental results

At high pressures k is strictly constant and independent of pressure, and 

When this condition is met, and only then, Equation (4.51) reduces to 

The pressure at which the observed first order rate constant has fallen to one-half of its high pressure value corresponds to 

Once k2 is found from experiment in this way, then k can be found from the experimental value of k,x,  

This will only be linear if k, k. and k2 are constants, in which case the graph will have slope = jk and intercept = k. jk k2. This gives an alternative route to k2, again provided k i is known. 

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