12.07.2015 Views

Practice of Kinetics (Comprehensive Chemical Kinetics, Volume 1)

Practice of Kinetics (Comprehensive Chemical Kinetics, Volume 1)

Practice of Kinetics (Comprehensive Chemical Kinetics, Volume 1)

SHOW MORE
SHOW LESS
  • No tags were found...

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

3CHEMICAL RELAXATION METHODS129._ 6B+0U C8c y - . . . . .ITime -Fig. 5. <strong>Chemical</strong> relaxation in terms <strong>of</strong> the step-function model.reaction state in which there is no net rate <strong>of</strong> transformation, such as that foundat a fixed distance from the mixer in a flow-mix experiment, it is convenient to makethe derivation <strong>of</strong> relaxation times as general as possible.The full line in Fig. 5 represents the concentration <strong>of</strong> species i at times before andafter the application <strong>of</strong> the step-function (dashed line). cp is a time-independentreference concentration, while Ci is the corresponding (final) equilibrium value whichmight be time-dependent. Thenxi = ci-coand Xi = Zi-ci0and the rate can be written asi.e.,- d(Xi -xi) = (l/T)(Xi-xi)dtprovided that (Zi- xi)

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!